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AMERICAN   TEACHERS   SERIES 

\. 

EDITED   BY 

JAMES   E.  RUSSELL,  PH.D. 

DEAN   OF  TEACHERS   COLLEGE,   COLUMBIA   UNIVERSITY 


THE 

TEACHING    OF    CHEMISTRY    AND    PHYSICS 
IN    THE   SECONDARY   SCHOOL 

BY 

ALEXANDER    SMITH 

AND 

EDWIN    H.  HALL 


The  Teaching  of  Chemistry  and 

Physics  in  the  Secondary 

School 


BY 
ALEXANDER  SMITH,  B.Sc.,  PH.D. 

ASSOCIATE   PROFESSOR   IN  THE   UNIVERSITY   OF  CHICAGO 
AND 

EDWIN  H.  HALL,  PH.D. 

PROFESSOR    IN    HARVARD    UNIVERSITY 


UNIVERSITY 

• 


LONGMANS,  GREEN,  AND  CO. 

91  AND  93  FIFTH  AVENUE,  NEW  YORK 

LONDON   AND   BOMBAY 

1902 


It) 


REESE 

Copyright,  1902 
By  LONGMANS,  GREEN,  AND  Co. 


.<4//  rights  reserved 


UNIVERSITY    PRESS    •   JOHN   WILSON 
AND    SON    •     CAMBRIDGE,     U.S.A. 


Editor's   Note 

THE  present  volume  in  the  American  Teachers  Series  follows 
the  lines  marked  out  in  the  preface  to  the  first  volume.  No 
effort  has  been  made  to  bias  or  harmonize  the  views  of  the 
authors.  It  has  been  deemed  better  to  have  a  logical  presen- 
tation, even  at  the  risk  of  disagreement,  than  to  give  the  impres- 
sion that  there  is  only  one  way  of  conceiving  or  giving  class 
instruction.  These  volumes  are  intended  as  teachers'  helps, 
and  their  purpose  is  served  if  they  are  suggestive  to  teachers 
who  are  earnestly  seeking  for  improvement. 

The  authors  of  the  separate  parts  on  Chemistry  and  Physics 
have  conferred  frequently  during  the  progress  of  the  work,  and 
have  endeavoured  to  avoid  unnecessary  duplication.  There 
are  thus  some  subjects  of  equal  importance  to  teachers  of 
chemistry  and  physics  which  are  discussed  in  one  of  the  sec- 
tions only.  Some  references,  equally  suited  to  either  part, 
appear  only  once  for  the  same  reason.  In  a  few  instances, 
however,  the  divergence  between  the  opinions  of  the  authors 
seemed  to  make  it  desirable  that  each  should  present  his  own. 


JAMES    E.    RUSSELL. 


TEACHERS  COLLEGE, 

COLUMBIA  UNIVERSITY. 


O  Q  f*  :T  o 


Contents 


THE   TEACHING   OF   CHEMISTRY   IN   THE 
SECONDARY   SCHOOL 

CHAPTER    I 

INTRODUCTION 

PAGE 

I.     Reasons  for  the  Study  of  Science 8 

II.     History  of  Chemical  Instruction 18 

III.     Present  Condition  of  Chemical  Instruction     ....       21 


CHAPTER   II 
CHEMISTRY   IN   THE    CURRICULUM 

I.     Precedence  of  Physics 29 

a.  The  Report  of  the  Committee  of  Ten    ....       29 

b.  Observations  in  Chemistry  a  Study  of  Physical 

Properties 30 

c.  The  Conclusion 33 

II.     Arguments  in  Favour  of  the  Precedence  of  Chemistry       33 

III.     In  which  Year  of  the  High  School  Course  shall  Chem- 
istry be  taught  ? 37 

IV.     The  Time  to  be  allotted  to  Chemistry 40 

V.     Continuous  Courses  in  Chemistry 42 

VI.     Articulation  of  School  and  College  Chemistry   ...  44 

CHAPTER    III 
THE   INTRODUCTION   OF  THE   SUBJECT 

I.     Impediments  to  be  overcome  or  avoided 49 

II.     What  Phenomena  shall  furnish  the  Basis  of  the  Intro- 
ductory Work  ? 52 

a.  Classification  of  Various  Principles  of  Arrange- 
ment   53 


viii  CONTENTS 

PAGE 

b.  Various  Arrangements  illustrated  by  Reference  to 

existing  Text-Books 55 

c.  The    Present    Ideal   of    the    Secondary   School 

Course  in  Chemistry 60 

III.     Earlier  Generalizations  of  a  Qualitative  Nature  .     .     .  69 

IV.     Further  Generalizations  of  a  Quantitative  Character   .  72 
V.     The  Relation  of  the  Quantitative  Laws  to  Formulae  and 

Equations 77 


CHAPTER    IV 
INSTRUCTION    IN   THE    LABORATORY 

I.     The  Value  of  Laboratory  Work  for  General  Education  87 

a.  For  teaching  Knowledge-making  by  Observation 

and  Induction 87 

b.  For  teaching  Knowledge-making  by  the  Study  of 

Natural  Objects  and  Phenomena      ....  87 

c.  For  teaching  Caution  and  Mental  Rectitude    .     .  89 

d.  Other  Benefits  of  a  General  Nature 90 

II.  The  Value  of  Laboratory  Work  for  Instruction  in  Chem- 
istry    90 

a.  For  giving  First-hand  Knowledge 90 

b.  For  holding  Interest  and  Attention 91 

c.  For  securing  Clear  and  Pregnant  Expression       .  92 

III.  The  Laboratory  Directions 94 

a.  Laboratory  Directions  should  be  coherent       .     .  94 

b.  Main  Points  in  regard  to  the  Directions  for  each 

Experiment 97 

c.  Selection  of  Experiments 100 

d.  An  Illustration JO2 

IV.  The  Pupil  and  his  Attitude      . 105 

a.  The  Verification  of  Laws 106 

b.  The  Attitude  of  Discoverer;  the  Heuristic  Method  106 

c.  Summary 1 10 

V.     Laboratory  Technique in 

VI.     Quantitative  Experiments 113 

a.  Limitations 114 

b.  Equipment  for  Quantitative  Experiments  .     .     .  115 

c.  Suitable  Quantitative  Experiments 117 


CONTENTS  ix 

PAGE 

d.  The  Application  of  Quantitative  Experiments     .  119 

e.  Benefits  and  Objections 120 

VII.     The  Role  of  the  Teacher  in  the  Laboratory     ...  122 

VIII.     The  Note-book 123 

IX.     Emergencies 125 


CHAPTER  V 
INSTRUCTION   IN   THE   CLASSROOM 

a.  Oral  and  Written  Quizzes 128 

b.  Experimental  Demonstrations 133 

c.  Stoichiometric  Problems 135 

d.  Use  of  the  Text-book 136 

e.  The  Importance  of  keeping  the  Subject  in  Contact 

with  E  very-day  Life 138 

f.  Necessity  for  Unification  of  the  Whole       .     .     .  143 

g.  Some  Misleading  Words 144 

h.  Some  Common  Fallacies 145 

i.  The  Grammar  of  Science 146 


CHAPTER   VI 
SOME   CONSTITUENTS   OF   THE   COURSE 

I.     Th*  Atomic  Theory:  its  Nature  and  Place  in  Elemen- 
tary Instruction 154 

a.  The  Atomic  Theory  not  a  Fact 1 54 

b.  Its  Limited  Application 156 

c.  The  Place  of  the  Theory  in  Elementary  Instruc- 

tion      158 

II.     The  Treatment  of  Valency 162 

III.  Use  of  the  Results  of  Physico-chemical  Investigation  .  165 

IV.  Shall  Qualitative  Analysis  be  included,  and  if  so,  in 

what  Form  ? 171 

a.  Arguments  in  Favour  of  Qualitative  Analysis       .  172 

b.  Arguments  against  Qualitative  Analysis     .     .     .  173 

c.  Exercises  in  Identification 178 

V.     The  General  Content 182 

VI.     The  Selection  of  the  Text-Book  and  Laboratory  Manual  184 


CONTENTS 


CHAPTER  VII 

THE   LABORATORY,  EQUIPMENT   AND   ILLUSTRATIVE 

MATERIAL 

PAGE 

I.     Accommodations  required 187 

II.     Laboratory  Furniture 189 

a.  The  Desks 189 

b.  The  Hoods 191 

c.  The  Side-shelves 192 

d.  Other  Laboratory  Furniture 193 

III.  Laboratory  Equipment 193 

IV.  Apparatus  and  Chemicals,  and  the  Store-room  .     .     .  195 
V.     The  Classroom  and  its  Fittings 200 

VI.     Illustrative  Material 201 

VII.     The  Teacher's  Private  Room 206 

CHAPTER     VIII 

THE   TEACHER,  HIS    PREPARATION   AND 
DEVELOPMENT 

I.     The  Training  of  the  Teacher 207 

II.     The  Development  of  the  Teacher  during  Professional 

Life 214 

III.     Literature  for  the  Teacher 218 


THE   TEACHING   OF   PHYSICS   IN   THE 
SECONDARY   SCHOOL 

CHAPTER    I 

WHETHER  TO   BE   A   TEACHER   OF  PHYSICS 
Motives  Influencing  Decision.    Natural  Qualities  Needed     233-237 

CHAPTER    II 
PREPARATION   FOR   TEACHING 

Objects  of  Education  in  Science.     The  Teacher  should  be 
able  to  Advise.     Ph.D.  or  A.M.  for  the  Teacher?     Sup- 


CONTENTS  xi 

PAGE 

plementary  Studies.      Knowledge  of    History  of  Physics. 
Habit  of  General  Observation.     Study  of  Art  of  Teaching 

238-246 

CHAPTER    III 

THE    TEACHER  AS    STUDENT,  OBSERVER,  AND 
WRITER 

Original  Research  ?  Work  akin  to  Research.  Physics  out 
of  Doors.  Change  and  Variety.  Writing  and  Speaking 

247-252 

CHAPTER  IV 
PROBLEMS  OF  LABORATORY  PRACTICE 

Water-Proofing  Wooden  Blocks.  Correction  and  Use  of 
Spring  Balance.  Use  of  Platform  Balance.  Preparation 
of  Apparatus  for  Measurement  of  Expansion  of  Air  .  253-266 


CHAPTER   V 

SCHOOL  TEXT-BOOKS  OF  PHYSICS 
Retrospect.  General  Information.  Type  of  Book.  Change 
of  View  and  Method.  Harvard  College  Action  on  Physics 
for  Admission.  Influence  of  Harvard  "Descriptive  List." 
A  Revision.  Influence  of  Ann  Arbor.  No  All-sufficient 
Text-Book 267-273 

CHAPTER   VI 
DISCOVERY,  VERIFICATION,   OR   INQUIRY? 

"  Inductive  and  Deductive."  Abuses  of  "  Inductive 
Method."  Art  of  Discovering  General  Laws  cannot  be 
Taught.  Verification.  Prejudice  perverts  Evidence. 
Method  of  Inquiry ;  Illustrations.  Inaccuracy  of  Some 
"Laws."  Pooling  of  Observations  in  Difficult  Inquiries; 
Illustrations :  Laws  of  Bending,  Acceleration,  Test  of  Mass, 
Action  and  Reaction,  Density  of  Air.  Pupils'  Blunders. 
Repetition  of  Exercises 274-288 


CONTENTS 


CHAPTER   VII 

THE  TECHNIQUE  OF  LABORATORY  MANAGEMENT 

PAGE 

Report  on  Methods  by  Committee  of  Eastern  Association 
of  Physics  Teachers.  Even-Front  Progression.  Wasteful- 
ness of  Irregular  Order  of  Progression.  Reduplication  of 
Apparatus.  Size  of  Laboratory  Section.  Individual  or 
Group  Work  ?  Length  of  Laboratory  Exercise.  The 
Teacher's  Preparation  of  Work.  Use  of  a  Manual.  The 
Pupil's  Preparation.  Record  of  Laboratory  Work ;  Illus- 
tration. Time  and  Place  for  Calculations.  Oversight  of 
Note-Book.  First  Record  should  Stand.  "  Data  Slips  " 
and  "  Result  Slips  "  for  "  Scrap-Book  "  Record.  Lessons 
from  Laboratory  Work.  Care  of  Apparatus.  Relief  from 
Manual  Labor 289-303 

CHAPTER  VIII 
LECTURES   AND    RECITATIONS 

Laboratory  Work  not  Enough.  Function  of  Lectures,  etc. 
Abuse  of  the  "  Quiz."  Numerical  Problems.  Preparation 
for  Lectures.  Lecture-Room  Galvanometers.  Projecting 
Lantern.  Qualitative  Experiments.  Applications  of  Physics. 
Care  for  Form  in  Lectures 3o4-3r5 


CHAPTER   IX 
PHYSICS  IN   PRIMARY  AND  GRAMMAR  SCHOOLS 

"  Nature  Study."  Children's  Experimental  Knowledge. 
Difficulty  with  Words.  Qualitative  or  Quantitative  Work? 
Need  of  Progress.  Physics  in  Grammar  Schools  of 
Cambridge 316-323 

CHAPTER   X 

PHYSICS    IN   VARIOUS   KINDS    OF  SECONDARY 

SCHOOLS 

College  Entrance  Physics  of  the  National  Educational 
Association.  History  of  the  N.  E.  A.  Report.  Detailed 


CONTENTS  xiii 

PAGE 

List  of  Exercises.  Action  of  Middle  States  Board.  Dif- 
ference between  Preparatory  and  Non-Preparatory  Schools. 
What  High  Schools  should  do.  Physics  in  the  High  School 
of  Brookline 324-340 

CHAPTER   XI 
ON   THE   PRESENTATION   OF   DYNAMICS 

Difficulty  of  the  Subject  Increased  by  Poor  Teaching. 
Multiplicity  of  Force-Units.  Tabulation  of  Equations. 
Mass  in  the  Language  of  Engineering 341-347 

CHAPTER   XII 
PLAN   AND   EQUIPMENT   OF  A   LABORATORY 

Working  Tables.  The  Laboratory-room,  Apparatus-cases, 
etc.  Workshop.  Lecture-room.  Some  Equipments. 
General  Apparatus 348-355 

CHAPTER   XIII 

PHYSICS   TEACHING   IN   OTHER  COUNTRIES 
In  Germany.     In  England.     In  France 356-371 

INDEX 373 


THE   TEACHING    OF    CHEMISTRY    IN 
THE   SECONDARY   SCHOOL 

BY  ALEXANDER    SMITH,  B.Sc.    PH.D. 
ASSOCIATE  PROFESSOR  OF  CHEMISTRY  IN  THE  UNIVERSITY  OF  CHICAGO 


Prefatory  Note 


WHILE  there  is  only  one  science  of  chemistry,  there  are  many 
opinions  on  the  teaching  of  it.  A  tendency  to  seeming  dogma- 
tism is  almost  unavoidable  in  writing  on  the  subject.  It  can 
only  be  said  that,  by  an  attempt  to  present  the  various  views, 
even  where  there  is  a  very  distinct  inclination  towards  one  view 
on  the  part  of  the  majority  of  chemists,  an  effort  has  been 
made  to  avoid  real  intolerance.  The  references  to  articles  and 
books  dealing  with  all  controversial  points  will  enable  the  reader 
to  acquaint  himself  with  the  best  that  can  be  said  for  each 
opinion  by  its  special  advocates  and  to  reach  a  decision  for 
himself.  Where  the  writer  has  felt  certain  that  fundamental 
faults  are  committed  by  any  considerable  number  of  the  less 
well-trained  teachers,  as,  for  example,  in  connection  with 
equations,  the  atomic  theory,  natural  law,  etc.,  the  view  held  to 
be  correct  may  appear  to  have  been  presented  in  an  extreme 
form  or  with  needless  vigour.  Perhaps  it  is  hardly  necessary  to 
explain  that  the  precise  treatment  given  here  in  such  cases  is 
not  necessarily  suited  as  it  stands  for  the  consumption  of  the 
pupil.  If  it  impresses  the  teacher  strongly  by  putting  a  different 
view  in  high  relief,  and  shows  him  the  standpoint  of  the  chemist 
as  opposed  to  that  of  some  pedagogues,  it  will  have  served  its 
purpose. 

The  book  assumes  the  reader's  familiarity  with  the  science. 
Many  brief  references  to  chemical  matters  would  have  been 
greatly  expanded  or  carefully  limited  if  they  had  been  intended 
for  beginners. 

There  has  been  no  intention  to  recommend  particular  text- 
books. Many  have  been  cited  as  possessing  some  point  of 
special  excellence,  but  this  must  not  be  taken  to  indicate 


4  THE    TEACHING   OF  CHEMISTRY 

emphatic  approval  of  those  works  as  wholes,  say  for  use  with  a 
class  of  beginners. 

The  author  is  indebted  to  many  friends  for  helpful  sugges- 
tions. Special  thanks  are  due  to  Messers.  J.  B.  Tingle,  Illinois 
College,  M.  S.  Walker,  West  Division  High  School,  Chicago, 
W.  A.  Noyes,  Rose  Polytechnic  Institute,  and  J.  B.  Garner, 
Wabash  College,  who  have  read  all  the  work  in  manuscript  or 
proof. 

ALEXANDER   SMITH. 

THE  UNIVERSITY  OF  CHICAGO, 
March,  1902. 


OF  THE 


The 


Teaching  of  Chemistry  in  the 
Secondary  School 


CHAPTER   I 

INTRODUCTION 
BIBLIOGRAPHY. 

Spencer,  Herbert.  Education,  Intellectual,  Moral  and  Physical. 
London,  Williams  &  Norgate.  New  York,  D.  Appleton  &  Co.  1860. 

Bain,  Alexander.  Education  as  a  Science.  London,  Kegan  Paul, 
Trench  &  Co.  New  York,  D.  Appleton  &  Co.  1881. 

Macgregor,  J.  G-.  The  Utility  of  Knowledge-making  as  a  Means  of 
Liberal  Training.  NATURE,  LXI.  (1899),  159-163;  extracts  in  SCHOOL 
REVIEW,  VIII.  (1900),  372. 

Eliot,  C.  W.  Educational  Reform.  New  York,  The  Century  Co. 
1898. 

Mach,  Ernst.  On  Instruction  in  the  Classics  and  the  Sciences. 
Popular  Scientific  Lectures.  Chicago,  The  Open  Court  Publishing  Co. 
London,  Kegan  Paul,  Trench  &  Co.  1895. 

Coulter,  J.  M.  The  Mission  of  Science  in  Education.  SCIENCE 
[N.  S.],  XII.  (1900),  281-293. 

"Wilson,  C.  C.  What  is  the  Consensus  of  Opinion  as  to  the  Place  of 
Science  in  the  Preparatory  Schools  ?  SCHOOL  REVIEW,  VI.  (1898), 
203-211. 

Huxley,  T.  H.  Science  and  Education.  Collected  Essays,  Vol.  III. 
London  and  New  York,  Macmillan.  1893. 

Perkin,  W.  H.,  Jr.  The  Modern  System  of  Teaching  Practical  In- 
organic Chemistry  and  its  Development.  Vice-Presidential  Address. 
Report  of  the  British  Association,  1900.  Reprinted  in  NATURE,  LXII. 
476-481. 

Perkins,  A.  S.  Elementary  Chemistry  in  the  High  School.  SCHOOL 
SCIENCE,  I.  72-77. 

Williams,  R.  P.  The  Teaching  of  Chemistry  in  Schools,  1876-1901. 
SCIENCE  [N.  S.],  XIV.  100-104. 

Long,  J.  H.  Early  History  and  Present  Condition  of  the  Teaching 
of  Chemistry  in  the  Medical  Schools  of  the  United  States.  Vice-Presi- 


6  INTRODUCTION 

dential  Address  before  the  American  Association  for  the  Advancement  of 
Science  (1901).  Reprinted  in  SCIENCE  [N.  S.],  XIV.  360-372. 

Russell,  J.  E.  German  Higher  Schools.  New  York  and  London, 
Longmans,  Green  &  Co.  1899.  PP-  329-351- 

Cooley,  LeR.  C.  Science  for  Education.  Presidential  Address  be- 
fore the  New  York  State  Science  Teachers'  Association.  High  School 
Bulletin  No.  7.  Albany,  N.  Y.,  The  University  of  the  State  of  New 
York.  Pp.  578-594- 

Butler,  N.  M.  The  Scope  and  Functions  of  Secondary  Education. 
EDUCATIONAL  REVIEW,  XVI.  (1898),  15-27. 

IN  introducing  the  subject  of  the  teaching  of  chemistry  it  is 
fitting  first  to  state  as  briefly  as  may  be  some  of  the  reasons  for 
the  inclusion  of  this  study  in  the  curriculum  of  the  secondary 
school.  We  shall  thus  have  in  hand  the  key  to  the  point  of 
view  which  will  be  preserved  in  the  treatment  of  the  subject  as 
a  whole,  and  our  statements  will  indicate  the  ideal  towards  which 
the  means  of  education  that  we  may  discuss  are  to  be  directed. 
Since  the  ideal  which  we  set  before  ourselves  must  be  brought 
into  relation  with  the  actual  conditions,  it  will  be  advisable  also 
to  say  something  in  regard  to  the  present  state  of  chemistry  in 
the  secondary  schools  of  this  country.  We  shall  then  be  able 
more  easily  to  determine  the  means  by  which  the  actual  may  be 
converted  into,  or  at  least  be  brought  to  approach  this  ideal. 

In  advocating  the  study  of  a  science,  all  intention  of  regarding 

it  as  the  only  worthy  means  of  education,  and  of  urging  that  it 

shall  supplant  other  subjects,  must  be   discarded. 

Reasonsfor  ^  *s  true  ^at  ^e  suPPort  °f  no  mean  authority 
the  study  of  might  be  found  even  for  this  radical  position. 
Herbert  Spencer,  in  his  chapter  on  "  What  knowl- 
edge is  of  most  worth,"  attempts  to  show,  and  with  some  success, 
that  the  information  which  the  study  of  science  furnishes  is  incom- 
parably more  useful  for  our  guidance  in  life  than  any  other  kind. 
Q  Starting  from  the  thesis  that  education  is  intended  to  teach  us 
how  to  live,  and  considering  all  the  activities  of  human  life,  he 
demonstrates  that  science  furnishes  equally  in  all  cases  the  need- 
ful preparation.  Considering  next  its  use  as  a  discipline,  he 
concludes  "  that  for  discipline,  as  well  as  for  guidance,  science 
is  of  chiefest  value.  In  all  its  effects,  learning  the  meanings  of 


INTRODUCTION  7 

things,  is  better  than  learning  the  meanings  of  words.  Whether 
for  intellectual,  moral  or  religious  training,  the  study  of  sur- 
rounding phenomena  is  immensely  superior  to  the  study  of 
grammars  and  lexicons. '£J  He  contends  that  the  value  of  the 
information  furnished  by  history  and  consisting  of  a  mere  tissue 
of  names  and  dates  has  a  conventional  value  only.  On  the 
other  hand  an  acquaintance  with  Latin  and  Greek,  since  it  fur- 
nishes extra  knowledge  of  our  own  language,  but  can  be  of  value 
only  so  long  as  certain  languages  and  races  exist,  may  be  held 
to  have  a  value  that  is  at  least  quasi-intrinsic.  The  knowledge 
furnished  by  the  truths  of  science,  such  as  that  resistance  to  the 
motion  of  a  body  varies  as  the  square  of  the  velocity,  and  that 
chlorine  is  a  disinfectant,  are  truths  which  will  bear  on  human 
conduct  ten  thousand  years  hence  as  they  do  now,  and  can 
therefore  alone  lay  claim  to  true  intrinsic  value. 

While  we  cannot  doubt  the  great  and  in  many  ways  entirely 
wholesome  influence  which  Spencer's  views  have  exercised, 
we  may  be  permitted  to  point  out,  that,  in  supporting  the 
claims  of  some  particular  subject  or  class  of  subjects  to  inclusion 
in  a  course  of  education,  one  is  always  in  danger  of  comparing 
the  subject  he  favours  at  its  best,  and  in  the  ideal  form  it  may 
receive  at  the  hands  of  an  ideal  teacher,  with  other  subjects  at 
their  average  or  even  at  their  worst.  This  essay  was  written 
before  1860,  and  was  published  in  that  year  with  the  others  form- 
ing the  volume  on  education.  Perhaps  the  circumstances  of 
that  time  justified  much  of  what  is  said,  in  a  way  that  the  cir- 
cumstances of  the  present  would  not.  There  have  undoubtedly 
been  great  improvements  in  language  teaching  at  its  best  since 
that  time,  and  while  Spencer  states  that  "  science  forms  scarcely 
an  appreciable  element  in  our  so-called  civilized  training,"  and 
in  another  place  speaks  of  it  as  "  that  which  our  school  course 
left  almost  entirely  out,"  these  statements  could  not  be  made 
with  justice  in  the  same  form  at  the  present  time. 

Our  task  will  be  rather  to  show  that  science  undoubtedly  has 
an  aptitude  for  educational  employment  sufficient  to  make  it  a 
valuable  study.  We  may  fairly  say  also  that  its  use  is  justi- 


8  INTRODUCTION 


t 


fied  by  the  desirability  of  introducing  variety  into  our  means 
of  instruction.  This  must  increase  its  strength  and  effective- 
other  Reasons  ness  m  yiew  °f  tne  many-sidedness  of  the  inter- 
for  the  study  ests  and  therefore  of  the  avenues  of  approach  in 
each  individual  case,  and  of  the  differences  in  the 
tastes  of  different  individuals.  We  may  perhaps  even  go  so  far 
as  to  demand  its  employment  on  the  ground  that  in  some  direc- 
tions, even  at  its  average,  it  can  furnish  certain  constituents  of 
an  all  round  discipline  of  the  mind  more  easily  or  in  a  more 
conspicuous  degree  than  other  subjects  at  their  average. 

We  must  begin  with  characteristics  which  are  common  to  all 
science,  with  physical  science  chiefly  in  mind,  and  afterwards 
more  briefly  refer  to  the  special  claims  of  chemistry.  The  order 
in  which  the  reasons  for  the  study  of  science  are  given  is  not  so 
much  that  of  importance  as  that  of  convenience  of  presentation. 

I.     Reasons  for  the  Study  of  Science. 

f  Our  first  reason  for  the  study  of  science  rests  on  the  training 
in  observation  for  which  it  furnishes  the  opportunity.  To  use 
Training  in  the  common  expression,  the  employment  of  the 
Observation.  iaDOratOry  method  in  science  furnishes  an  exercise 
not  merely  for  the  senses  but  for  the  mind.  This  practice  of 
observation  is,  however,  common  to  all  forms  of  scholarship, 
and  is  applied  in  languages,  for  example,  as  persistently  as  in 
science.  But  in  the  latter  this  training  directs  attention  to 
material  objects,  and  so,  while  theoretically  the  same  process,  it 
awakens  an  interest  in,  and  develops  a  capacity  to  exercise  an 
entirely  different  and  most  worthy  set  of  activities.  Its  applica- 
tion to  the  study  of  nature  and  her  laws  gives,  as  nothing  else  can, 
a  distinct  view  of  the  universe  as  a  well-ordered  system.  As  Pres- 
ident Eliot  says  (Educational  Reform,  no),^The  student  of 
natural  science  scrutinizes,  touches,  weighs,  measures,  analyzes, 
dissects,  and  watches  things.  By  these  exercises  his  powers  of 
observation  and  judgment  are  trained,  and  he  acquires  the  pre- 
cious habit  of  observing  the  appearances,  transformations,  and 
processes  of  nature.  Like  the  hunter  and  the  artist,  he  has 


INTRODUCTION  9 

open  eyes  and  an  educated  judgment  in  seeing.  He  is  at  home 
in  some  large  tract  of  nature's  domain.'!/  Mach  (Scientific 
Lectures,  280)  makes  the  same  point  as  follows :  "  I  shall 
meet  with  no  contradiction  when  I  say  that  without  at  least  an 
elementary  mathematical  and  scientific  education  a  man  remains 
a  total  stranger  in  the  world  in  which  he  lives,  a  stranger  in  the 
civilization  of  the  time  which  bears  him.  Whatever  he  meets  in 
nature,  or  in  the  industrial  world,  either  does  not  appeal  to  him 
at  all,  from  his  having  neither  eye  nor  ear  for  it,  or  it  speaks  to 
him  in  a  totally  unintelligible  language."  This  interest  in  a 
knowledge  of  nature  is  an  essential  element  in  robust  life.  The 
study  of  books  alone,  at  its  worst,  often  submerges  the  victim  of 
it  in  an  unpractical  and  even  mediaeval  spirit  which  we  all  recog- 
nise as  characteristic  of  the  bookworm. 

LThe  second  reason  for  the  study  of  science  is  that  it  trains 
the  pupil  in  the  organization  of  his  observations  by  comparison 
and  induction.)  This  again  is  an  operation  not  by  Trainin  ln 
any  means  peculiar  to  scientific  work.  Every  Comparison 
human  being  from  the  earliest  months  of  his  exist-  and  ^t"**011' 
ence  onwards  is  occupied  in  the  co-ordination  of  the  observations 
he  makes,  and  in  building  up,  with  rapidly  increasing  speed,  a 
mass  of  rationalized  experience.  The  business  of  life,  when  it  is 
entered  upon,  is  promoted  by  the  same  processes.!  Consciously 
or  unconsciously  observations  are  made  and  generalizations  pro- 
duced from  them,  and  on  the  ability  to  do  this  correctly  the 
man  depends  for  his  success  in  lifej  This  has  been  called  by 
Professor  J.  G.  Macgregor 1  the  "  knowledge-making  "  process,  by 
which  he  means  that  separate  facts  do  not  constitute  knowledge 
in  themselves,  and  that  all  we  know  which  is  of  value  is  made 
by  putting  together  our  isolated  observations.  It  is  our  ability 
to  do  this  which  counts  in  scholarship  or  in  life,  and  it  is  this 
therefore  which  education  should  be  specially  directed  to  culti- 
vate. As  Professor  Macgregor  points  outs,  the  old  curriculum, 
and  particularly  the  study  of  the  classics,  affords  abundant  op- 

1  In  a  most  interesting  inaugural  address  delivered  at  the  opening  of 
the  fortieth  session  of  Dalhousie  College  and  printed  in  full  in  NATURE. 


TO  INTRODUCTION 

portunity  for  the  exercise  of  this  power.  The  study  of  language 
involves  the  continual  putting  together  of  instances  of  the  use 
of  words  and  phrases.  "The  lexicon,"  he  continues,  "would 
give  little  more  than  a  clew  in  many  cases  to  the  English  equiva- 
lents of,  say,  Latin  words,  the  exact  equivalents,  whether  words 
or  phrases,  being  determinable  only  by  the  study  of  the  context 
and  the  fruitful  drawing  upon  experience." 

There  are  two  differences  between  this  process  as  carried  out 
in  the  study  of  a  language  and  the  same  process  employed  in 

the  study  of  a  science.     In  handling  the  grammar, 
Differences         ,.     .         J         ,  .    .       . 

between  Work  dictionary  and  text,  it  is  almost  impossible  for  this 

inLan|uag;es  instruction  in  its  early  stages,  and  at  all  events  at 
'  its  average  if  not  at  its  best,  to  avoid  confirming  the 
tendency  usually  fostered  by  ordinary  home  training  of  relying 
upon  authority  for  information  and  opinions.  Even  the  most 
elementary  work  in  science  must  be  considerably  below  the 
average  if  it  does  not  place  the  experimental  facts  themselves 
before  the  pupil,  and  suggest  to  him  no  other  ultimate  source 
of  information,  whether  for  the  learner,  the  teacher,  or  the 
author  of  thejext-book,j;han  the  study  of  nature  itself.  The 
other  advantage  which  natural  science  possesses  is  that  experi- 
ment permits  the  repeated  production  of  every  fact  fresh  from 
its  original  source  in  the  order  of  nature,  as  often  as  may  be 
necessary  for  its  full  appreciation,  and  with  such  variations  in 
its  circumstances  and  surroundings  as  a  clear  view  of  every  side 
of  it  may  demand.  The  method  of  experimoiit  is  a  tower  of 
strength  in  the  study  of  the  facts  of  science,  while  its  applica- 
tion to  languages  is  usually  discouraged  by  the  teacher,  and  its 
use  in  history  is  impossible.  The  recourse  in  this  way  to  the 
study  of  the  thing  itself  for  first  hand  information,  the  exactness 
and  conclusiveness  with  which  every  fact  may  be  established,  • 
the  testing  of  every  inference  or  hypothesis  by  renewed  com- 
parison with  facts,  form  the  essence  of  the  scientific  method.  ,  ij 
While  it  is  employed  as  far  as  possible  in  all  scholarly  work,  yet 
it  was  first  recognised  by  logicians  in  connection  with  the  rapid  "^ 
growth  of  science  which  resulted  from  its  systematic  application 


I  NT  ROD  UCTION  1 1 

in  the  study  of  nature,  and  it  still  finds  special  opportunities  of 
employment  along  scientific  lines  which  are  lacking  in  other  di- 
rections. It  is  not  too  much  to  expect  that  the  practice  of  this 
universally  applicable  method  on  the  original  material  will  form 
an  invaluable  foundation  for  its  subsequent  use  in  any  direction 
whatever.  As  Professor  Jebb  says  :  "  The  diffusion  of  that  which 
is  specially  named  science  has  at  the  same  time  spread  abroad 
the  only  spirit  in  which  any  kind  of  knowledge  can  be  prose- 
cuted to  a  result  of  lasting  intellectual  value." 
I"  Amongst  the  possibilities  which  the  study  of  a  science  promi- 
nently presents  is  that  of  the  exercise  and  control  of  the  imagi- 
nation.] In  connection  with  every  subject  of  thought  Useof  tte 
it  is  a  function  of  the  mind  to  rearrange  the  various  Imagination 
conceptions  which  are  presented,  to  recombine  them 
in  new  forms,  and  to  invent  hypotheses  which  justify  the  new 
combinations.  Of  all  the  powers  of  the  mind  it  is  certainly 
that  which  is  most  important  in  giving  originality  to  the  results 
of  thought.  But  in  proportion  to  its  value  and  activity  is  the  diffi- 
culty in  controlling  its  operations.  The  imagination  is  a  good 
servant,  but  a  bad  master.  ^The  opportunity  which  is  offered  in 
an  experimental  science  to  test  the  results  of  the  work  of  the 
imagination  by  comparison,  again  and  again  renewed,  with  the 
concrete  materials  with  which  it  has  been  dealing,  furnishes  an 
unrivalled  opportunity  to  practise  the  control  of  it]  To  parody 
Dr.  Johnson's  aphorism  about  Richardson^  the  study  of  science 
must  do  much  towards  teaching  the  imagination  to  move  at 
the  command  of  truth. 

As  Professor  John  M.  Tyler  says l :  "  The  successful  scientist 
will  always  exercise  his  own  imagination  and  that  of  his  pupils. 
He  will  not  allow  '  This  valuable  gift  of  nature  to  be  repressed 
by  a  bookish  and  wordy  education.'  He  will  encourage  no  day- 
dreaming fancy.  He  will  demand  that  the  pictures  of  the  imag- 
ination shall  be  rigidly  tested  to  see  that  they  correspond  to 

1  The. Culture  of  the  Imagination  in  the  Study  of  Science;  SCHOOL 
REVIEW/ VI.  (1898),  716.  The  whole  article  should  be  read.  See 
also  Pearson's  Grammar  of  Science,  chapter  I. 


1 2  IN  TROD  UCTION 

some  objective  reality.  But  within  these  limits,  and  with  these 
restrictions,  the  student  of  science  will  cultivate  his  imagination 
as  faithfully  as  the  student  of  art.  And  he  will  train  it  and 
control  it  with  far  more  scrupulous  fidelity." 
[_  The  study  of  science  gives  training  in  what,  for  want  of  a 
better  name,  we  may  designate  self-eliminationj  In  all  subjects 
s  if  11  in  c^ear  an(l  unbiased  judgment  is  the  ultimate  goal  of 
tion  in  Science  the  student's  effort,  but  many  branches  of  knowledge 
Work'  are  so  filled  with  human  opinions,  permeated  by 

conventional  standards,  and  all  through  show  so  strongly  the 
stamp  of  human  workmanship,  that  unprejudiced  judgment  is 
hard  to  attain.  Professor  Coulter,  in  an  address  delivered  at 
the  University  of  Michigan,  presents  clearly  the  idea  I  wish  to 
convey : — 

]  "  The  general  effect  of  the  humanities  in  a  scheme  of  educa- 
tion may  be  summed  up  in  the  single  word  appreciation.  They 
seek  so  to  relate  the  student  to  what  has  been  said  or  done  by 
mankind,  that  his  critical  sense  may  be  developed,  and  that 
he  may  recognise  what  is  best  in  human  thought  and  action]] 
To  recognise -what  is  best  involves  a  standard  of  comparison. 
In  most  cases  this  standard  is  derived  and  conventional ;  in  no 
case  is  it  founded  in  the  essential  nature  of  things,  in  absolute 
truth,  for  it  is  apt  to  shift.  In  any  case  the  student  injects 
himself  into  the  subject ;  and  the  amount  he  gets  out  of  it  is 
V  measured  by  the  amount  of  himself  he  puts  into  it.  It  is  the 
N  artistic,  the  aesthetic,  which  predominates,  not  the  absolute. 
It  is  all  comparative  rather  than  actual.  The  ability  to  read 
between  the  lines  is  certainly  the  injection  of  self  into  the  sub- 
ject-matter, and  the  whole  process  may  be  regarded  as  one  of 
self -injection  in  order  to  reach  the  power  of  appreciation.  .  .  . 
The  proper  and  distinctive  intellectual  result  of  the  sciences  is 
a  formula,  to  obtain  which  there  must  be  rigid  self -elimination. 
Any  injection  of  self  into  a  scientific  synthesis  vitiates  the  result. 
The  standard  is  not  a  variable,  an  artificial  one,  developed  from 
the  varying  tastes  of  man,  but  absolute,  founded  upon  eternal 
truth." 


IN  TROD  UCTION  1 3 

Of  course  neither  of  these  qualities  of  self-injection  and  self- 
elimination  is  confined  to  the  branch  of  knowledge  in  which  it 
is  thus  discovered  to  be  a  conspicuous  constituent.  As  Profes- 
sor Coulter  points  out,  even  in  the  study  of  science  alone  the 
self-injecting  tendency  of  the  humanities  must  be  combined 
with  the  self-eliminating  tendency  of  science,  "  and  the  power 
of  appreciation  developed  by  the  humanities  must  always  be 
tempered  by  the  scientific  spirit."  Each  method  is  needed  in 
the  study  of  both.  Objective  and  dispassionate  study  is  the 
result  of  the  application  of  the  scientific  method  in  any  field  of 
knowledge,  but  the  material  of  the  sciences  favours  the  achieve- 
ment of  this  ideal  in  an  especial  degree.  As  Huxley  says,  the 
scientific  mind  is  "a  clear,  cpld^Jogic^ engine,  with  all  its  parts 
of  equal  strength,  and  in  smooth  working  order." 
L  Other  characteristics  of  mental  discipline,  such  as  the  way  in 
which  it  stimulates  mental  rectitude,  favours  clear  thought,  leads 
to  clear  expression,  etc.,  might  be  discussedj  They  are,  how- 
ever, either  implied  more  or  less  distinctly  in  those  already 
enumerated,  or  may  be  discussed  more  fitly  in  connection  with 
the  particular  parts  of  chemical  work  which  call  out  their  em- 
ployment. 

[_An  argument  of  a  different  kind  but  of  no  small  weight  is 
founded  upon  the  value  of  the  information  which  the  study  of 
science  imparts.  It  is  at  once  evident  that  a  study  Value  of  tiie 
which  has  strong  claims  on  account  of  its  disciplinary  J^^edby 
value  must  become  practically  indispensable  if  it  is  Science. 
able  simultaneously  to  furnish  information  which  is  useful  and 
can  be  obtained  in  no  other  way.  It  is  one  of  the  strong  points 
of  Spencer's  argument  in  the  chapter  on  "  What  knowledge  is 
of  most  worth  "  that  the  information  furnished  by  science  is  of 
this  kind.  In  learning  how  to  live  we  must  consider  the  activities 
which  make  up  lifej  Spencer  divides  these  into  those  con- 
cerned with  self-preservation,  those  concernetl  with  the  gaining 
of  a  livelihood,  those  concerned  with  the  rearing  of  offspring, 
those  which  minister  to  the  regulation  of  conduct  in  social  and 
political  relations,  and  those  which  minister  to  the  gratification 


14  INTRODUCTION 

of  our  tastes  and  feelings.  He  shows  in  great  detail  how  all- 
important  scientific  knowledge  is  for  success  in  any  of  these 
lines.  j^Huxley  has  used  the  same  argument,  and  puts  it  in  a 
very  striking  form.7  The  memorable  passage  in  one  of  his 
essays,1  in  which,  after  comparing  life  to  a  momentous  game 
with  complicated  rules,  he  asks  whether  a  parent  who  failed  to 
teach  his  son  the  rules  of  this  game  would  not  be  considered 
negligent  or  even  cruel,  is  so  familiar  that  to  recall  it  is  almost 
superfluous.  In  his  simile,  life  is  like  a  game  of  chess  with  an 
invisible  opponent,  who  may  be  regarded  if  you  will  as  some 
calm,  strong  angel,  who  plays  for  love,  as  the  saying  is,  and 
would  rather  lose  than  win.  The  rules  of  the  game  are  the  laws 
of  the  universe.  The  incompetent  player  is  checkmated  — 
without  haste,  but  without  remorse. 

I  Not  only  is  this  information  valuable,  nay,  indispensable,  in 
itself,  but  it  assists  in  holding  the  interest  of  the  majority  of 
pupils  who  would  not  be  so  much  attracted  by  a  purely  disci- 
plinary study]  Contact  with  physical  science  when  it  is  pre- 
sented in  the  right  way  must  continually  be  felt  to  be  contact 
with  a  mighty,  living,  and  growing  reality. 

There  is  still  another  consideration  which  cannot  be  left  out 
of  account  when  the  introduction  of  a  subject  into  the  currie- 
History  of  the  ulurri  is  proposed,  and  that  is  that  we  have  no 
Curriculum,  reason  to  believe  on  historical  grounds  that  the  old- 
curriculum  has  become  so  much  a  part  of  the  development  Of 
the  race  that  any  change  in  it  would  produce  serious  organic 
disturbance.  As  President  Eliot  has  clearly  shown,2  the 
classical  curriculum  is  only  three  hundred  years  old,  and  dis- 
placed after  a  severe  struggle  an  entirely  different  course  of 
training,  consisting  of  scholastic  theology  and  metaphysics, 
while  this  in  turn  was  simply  the  usurper  of  a  throne  formerly 
occupied  by  grammar,  rhetoric  and  logic,  with  a  little  mathe- 
matics, music  and  astronomy.  Thus  a  complete  revolution  of 
the  whole  list  of  studies  might  occur  again  without  scholarship 

1  A  Liberal  Education,  and  where  to  find  it.     Essays,  Vol.  III. 

2  What  is  a  Liberal  Education.     Educational  Reform,  94. 


I  NT  ROD  UC  TION      (p^  1 5 

becoming  a  byword  or  education  perishing  from  the  earth. 
Even  if  science  and  modern  languages  entirely  displaced  the 
classics,  we  could  not  urge  that  a  break  in  the  course  of  nature 
had  occurred,  but  only  that  history  was  repeating  itself.  This 
displacement,  however,  is  not  demanded.  All  we  make  is  a 
plea  for  the  fair  representation  of  science,  and  this  must  be 
regarded  as  conservative,  whether  we  look  at  it  in  the  light  of 
reason  or  of  history. 

pTo  sum  up,  we  may  fairly  claim  that  when  science  is  employed 
in  a  way  which  constitutes  an  approach  to  the  realization  of  its 
possibilities,  it  furnishes  a  field  for  observation  along 
a  special  line,  that  of  the  phenomena  of  nature ; 
it  exercises  us  in  knowledge-making,  and  for  this  furnishes  a 
method  of  unusual  power,  that  of  the  study  of  concrete  objects 
and  of  experiment ;  it  gives  employment  for  the  imagination, 
and  at  the  same  time  provides  an  especially  sure  means  of  con- 
trolling its  operations ;  it  trains  the  judgment  by  the  way  in 
which  the  nature  of  its  subject-matter  favours  self-elimination  ; 
and  finally,  the  information  which  it  yields  is  of  a  special  and 
particularly, valuable  description.,,  Other  subjects  may  claim  to 
provide  discipline  under  every  one  of  these  heads,  but  in  each 
case  science  gives  a  particular  variety  of  this  discipline  which  is 
distinctive.  It  is  thus  an  indispensable  complement  to  other 
branches  of  study,  and,  it  may  be  added,  is  indispensable  not 
merely  in  the  secondary  school,  but  at  every  stage  of  education.] 
This  is  the  least  that  can  be  said.  Many  scientific  men 
claim  more  for  it.  In  ascending  the  Brocken  one  sees,  at 
intervals  of  a  few  hundred  feet,  portions  of  ground  fenced  off 
and  used  for  the  rearing  of  small  trees  which  are  afterwards  to 
be  planted  out  at  the  same  altitude.1  If  the  same  trees  were 
sprouted  at  the  experiment  station  at  Goettingen,  and  then 
planted  at  the  top  of  the  Brocken,  so  far  as  even  an  authority 
on  forestry  could  see,  they  might  appear  to  be  perfectly 


1  I  have  adapted  this  illustration  from  the  highly  suggestive  presi- 
dential address  of  Professor  Dennis  on  "  The  School  and  the  World  " 
delivered  before  the  Indiana  State  Science  Teachers'  Association  (1898). 


1 6  INTRODUCTION 

adapted  to  the  purpose,  yet  they  would  have  less  chance  of 
surviving  in  their  changed  environment.  It  is  to  be  feared  that 
a  large  part  of  what  we  learn  in  school  does  not  survive  transr 
plantation  to  the  climate  of  the  world,  in  spite  of  the  demon- 
strable value  of  its  educational  possibilities.  Perhaps  before  we 
have  concluded  our  study  of  the  teaching  of  chemistry,  it  may 
appear  that  science  at  its  best  comes  nearer  to  being  a  form  of 
training  sprouted  at  the  right  altitude,  and  stands  a  better 
chance  of  thriving  in  every-day  life  than  book  learning  in  any 
other  branch. 

Some  objections  have  been  urged  against  the  conspicuous 
employment  of  the  sciences  as  aids  in  education.  It  is  said 
Objections  to  tnat  tne  metn°d  of  science  is  so  rigorous  and 
the  study  of  exact  that  it  unfits  men  for  dealing  with  human 
the  Sciences.  , .  .  .  .  ,  .  ,  . 

questions  which  have  not  the  same  clean-cut  qual- 
ities. Perhaps  the  best  answer  to  this  is  that  experience  has 
not  shown  that  men,  even  when  they  have  devoted  their  whole 
lives  to  the  study  of  science,  very  generally  lose  the  qualities  of 
sympathy  and  humanity.  And,  if  there  is  no  great  evidence  of 
this  in  their  case  (and,  in  this  connection,  surely  the  quotation 
of  Darwin's  experience  has  been  decidedly  overworked,  and 
been  manipulated  like  a  stage  army  until  it  has  furnished  an 
apparent  basis  for  generalization),  there  is  little  danger  of 
serious  atrophy  of  the  sensibilities  when  scientific  work  of  an 
elementary  character  occupies  but  a  fraction  of  the  time  of  our 
youth. 

It  is  said  also  that  the  study  of  science  tends  to  lower  the 
ideals  of  the  student,  since  it  calls  upon  him  to  soil  his  hands 
by  contact  with  that  which  is  commercially  useful,  and  that  its 
general  pursuit  would  convert  us  into  a  money-getting  and 
ease-loving  people.  I  believe  that  the  writing  and  publication 
of  books  for  beginners  in  various  languages  is  a  very  lucrative 
occupation,  but  I  have  not  heard  that  this  fact  diminishes  the 
cultural  value  either  of  the  instruction  given  by  the  author  or  of 
the  study  of  his  books.  Seriously,  it  is  not  proposed  that  a 
course  should  be  given  which  shall  in  the  remotest  way  suggest 


IN  TROD  UC  TION  1 7 

how  one  may  become  wealthy  by  the  employment  of  chemistry. 
There  are  many  teachers  of  chemistry  who  would  be  delighted 
to  attend  such  a  course,  however,  if  it  were  given. 

Finally,  it  is  stated  that  the  scientific  man  exercises  himself 
with  so  limited  a  part  of  human  experience,  as  compared  with 
that  touched  by  the  classics,  for  example,  that  the  study  of 
science  has  of  necessity  a  distinctly  narrowing  influence.  This 
argument,  and  the  preceding  one  as  well,  simply  seem  to  be 
fresh  cases  of  comparing  one  study  at  its  worst  with  another 
study  at  its  best.  Science  at  its  worst  under  a  poor  teacher  is 
doubtless  as  narrowing,  not  to  say  dull  and  useless,  as  any 
other  study  taught  under  the  same  conditions. 

So  far  we  have  spoken  of  science  in  general  with  the  thought 
of  physical  science  particularly  in  our  minds.  Some  of  the 
arguments  in  its  favour  hold  with  special  force  in  The  Sciences 
regard  to  the  biological  sciences,  and  indeed,  if  inthe  Curri- 
these  sciences  had  been  considered,  at  least  one 
weighty  addition  might  have  been  made  to  the  list.  We  are 
not  here  concerned  with  sciences  other  than  physical ;  nor  does 
any  question  arise  as  to  whether  physics  is  to  be  preferred  to 
chemistry  or  chemistry  to  physics.  Chemistry  can  be  studied 
only  through  physics.  The  latter  science  is  more  easily  ap- 
proached, furnishes  a  broader  field  and  more  points  of  contact 
with  every-day  life,  and  is  indeed  a  prerequisite  to  the  study  of 
any  science.  If  chemistry  is  studied  before,  or  instead  of 
physics,  about  half  the  time  at  the  disposal  of  the  teacher 
of  chemistry  must  be  devoted  to  the  study  of  physics,  or  the 
work  in  chemistry  itself  will  be  trivial  and  superficial. 

Chemistry  shares  with  physics  all  the  characteristics  of 
scientific  study  which  we  have  discussed.  It  differs  from  it 
slightly,  however,  in  respect  to  the  degree  and  manner  in 
which  some  of  them  are  represented.  Thus  in  chemistry  ob- 
servation is  mainly  through  the  study  of  physical  phenomena ; 
chemical  observation  is  therefore  made  by  inference  and  not 
directly.  Again,  the  facts  of  chemistry  which  have  to  be  taken 
into  consideration,  even  in  elementary  work,  are  much  more 


1 8  INTRODUCTION 

numerous  than  is  the  case  in  physics.  The  memory  is  much 
more  heavily  taxed  in  their  mastery,  and  the  powers  of  organi- 
zation are  called  more  prominently  into  play  in  their  arrange- 
ment. Without  unusual  emphasis  on  organization  and 
arrangement  the  science  disintegrates  into  a  mass  of  details. 
Finally,  the  study  of  chemistry,  on  account  of  the  indirect 
method  of  observation,  gives  more  employment  to  the  imagina- 
tion than  does  physics.  The  theories  and  hypotheses  of  chem- 
istry are  more  indispensable  to  the  appreciation  of  its  facts.  Of 
course,  as  regards  information,  the  sciences  are  all  distinct  from 
one  another,  and  there  is  little  to  choose  between  physics  and 
chemistry  in  the  matter  of  the  importance  of  this. 

II.     History  of  the  Teaching  of  Chemistry. 

While  the  discussion  centering  round  arguments  like  those 
we  have  set  forth  was  going  on,  the  sciences  had  been  slowly 
ripening  on  the  didactic  side  against  the  time  when  they 
should  gain  free  representation  in  the  schools  as  disciplinary 
studies. 

The  course  of  laboratory  instruction  in  the  earlier  days  of  all 

institutions  of  whatever  kind  seems  to  have  been  modelled  on 

that  pursued  by  Liebig  in  Giessen.     Here,  Professor 

Methods  oi 

instruction  Perkin  says,  "  after  preparing  the  more  important 
in  Chemistry.  gaseSj»  the  student  «  was  carefully  trained  in  quali- 
tative and  quantitative  analysis."  The  publication  of  an  out- 
line of  Liebig's  course  in  qualitative  analysis  by  Professor  Will 
in  1846  (this  was  the  first  systematic  introduction  to  the  subject 
for  the  use  of  beginners),  and  its  translation  into  English,  seem 
to  have  been  followed  by  the  adoption  of  this  subject  as  almost 
the  sole  material  of  elementary  laboratory  instruction.  Even  at 
the  present  day  the  tradition  still  retains  its  influence,  and  the 
importance  of  fuller  preliminary  instruction  in  general  chemistry 
is  still  righting  its  way  to  recognition  in  some  quarters.  The 
one-sided  and  distorted  view  of  chemistry  which  the  standpoint 
of  elementary  qualitative  analysis  gives  is  still  unfortunately  the 
only  one  offered  to  many  beginners. 


INTRODUCTION  19 

The  first  really  decisive  step  in  the  right  direction  was  taken 
by  Harvard  College,  when,  in  1888,  it  included  chemistry  for 
the  first  time  among  the  subjects  that  might  be  offered  for  ad- 
mission, and,  through  Professor  Cooke's  Laboratory  Practice^ 
issued  in  the  same  year,  defined  the  kind  of  work  which  it 
considered  to  be  the  true  educational  equivalent  of  the  other 
and  older  preparatory  school  studies.  This  book  practically 
launched  a  new  ideal  in  chemical  instruction.  It  was  the  first 
attempt  in  this  country  *  to  lay  out  a  course  of  laboratory  work 
dealing  adequately  with  the  fundamental  facts  and  laws  of 
chemistry.  The  result  was  in  marked  contrast  to  the  miscel- 
laneous experimentation  with  chemical  substances,  and  the 
dabbling  in  qualitative  analysis  which  had  hitherto  been  in  use 
and  had  afforded  so  little  support  to  the  classroom  work  on  the 
principles  of  the  science. 

In  Great  Britain  the  question  of  the  best  methods  of  teaching 
elementary  chemistry  had  been  under  discussion  for  some  years 
before  this  time.  In  1889  a  committee  of  the  British  Associa- 
tion, appointed  to  consider  the  subject,  submitted  a  report 
which  included  a  detailed  outline  of  work  (prepared  by  Pro- 
fessor Armstrong  for  the  Committee)  that  was  a  vast  improve- 
ment on  the  old  schemes  commonly  in  use.  It  resembled  the 
American  plan  in  discarding  analysis,  but  was  intended  for  a 
younger  set  of  pupils,  and  differed  from  it  besides  in  placing 
emphasis  even  more  strongly  on  the  method 'of  instruction  at  the 
expense  of  the  completeness  of  the  account  of  the  science.  It 
sought  to  place  the  pupil  as  completely  as  possible  in  the  attitude 
of  a  discoverer,  and  was  willing  to  sacrifice  much  in  the  way  of 
speed  and  area  covered  to  accomplish  this.  In  their  different 
ways  both  were  notable  contributions  to  the  didactic  side  of 
chemistry,  and  we  may  trace  directly  to  their  influence  the  rapid 
spread  of  more  rational  methods  of  teaching  the  science  which 
has  been  so  conspicuous  in  both  countries.  The  principle 


1  Professor  Ramsay's  Experimental  Proofs  of  Chemical  Theory  for 
Beginners  (London,  Macmillan,  1884)  was  the  corresponding  "first"  in 
Great  Britain. 


20  INTRODUCTION 

underlying  Professor  Cooke's  plan  has  been  adopted  by  nearly 
every  recent  work  prepared  for  the  use  of  secondary  schools. 
The  motif  ot  Professor  Armstrong's  report  has  coloured,  where 
it  has  not  controlled,  a  large  proportion  of  the  recent  teaching 
of  Great  Britain. 

In  Germany  some  work  in  science  is  given  in  every  year  of 
the  secondary  school  course.     The  instruction,  however,  seems 

to  be  undertaken  with  a  different   aim  from  that 
Chemistry  in 
the  Schools  of    kept   in   view  in   the    English-speaking   countries. 

Germany.  \vhile  in  this  country  chemistry  is  taught  as  a 
separate  department  of  instruction,  and  with  the  object  of  con- 
ferring some  knowledge  of  the  science  itself,  in  addition  to  the 
extraction  of  such  general  mental  discipline  as  its  study  is  able 
to  afford,  in  Germany  the  science  is  employed  primarily  for  the 
purpose  of  giving  intelligent  knowledge  of  things  around  us,  and 
as  a  means  of  training  the  powers  of  observation,  reasoning,  and 
exact  expression.  While  this  is  the  general  tendency,  however, 
there  are  many  schools  in  which  individual  laboratory  work  by 
the  pupils  is  included  in  the  curriculum,  and  in  which  the  place 
of  chemistry  is  more  like  that  which  it  holds  in  America  to- 
day. Yet  even  in  these  schools  the  laboratory  work  does 
not  call  for  fresh  study  of  new  problems  in  an  independent 
spirit,  but  only  repetition  of  those  already  used  and  illus- 
trated in  the  classroom.  Then,  too,  attendance  on  the 
laboratory  exercises  is  optional  and  is  usually  very  limited. 
Promotion  to  the  next  class  is  in  theory  dependent  on  pro- 
ficiency in  scientific  as  in  other  studies,  but  in  practice  takes 
place  irrespective  of  this.  Thus,  in  the  German  school, 
science,  to  use  the  words  of  Spencer,  is  "  the  household 
drudge,  who,  in  obscurity,  hides  unrecognised  perfections." 
At  least  these  perfections,  if  recognised,  are  veiled  until  the 
regular  study  of  the  sciences  as  separate  subjects  begins  in 
the  university.1 


1  See  James  E.  Russell,  German  Higher  Schools,  329-351,  in  which  a 
detailed  outline  of  the  work  in  physical  science  in  one  school  is  given, 
and  the  methods  and  ideals  are  fully  set  forth. 


INTROD  UCTION  2 1 

III0   The  Present  Condition  of  Chemical  Instruction. 

The  history  of  secondary  education  in  America  so  far  as 
chemistry  is  concerned,  has  been  marked  by  two  conflicts,  first, 
the  struggle  for  admission,  and  then,  the  struggle  for  xne  struggle 
rank.  The  struggle  for  admission  may  be  said  to  for  Admission. 
have  been  completely  won,  although  there  may  be  outlying 
portions  of  the  field  which  have  not  yet  been  occupied  by  the 
victor.  The  number  of  pupils  taking  chemistry  in  all  the 
secondary  schools  in  the  United  States  is  some  indication  of 
this.  According  to  the  report  of  the  Bureau  of  Education, 
8.55  per  cent  of  all  the  pupils  were  studying  chemistry  in 
1897-98.  When  we  consider  that  chemistry  is  very  rarely 
taught  during  more  than  one  year,  and  that  it  is  usually  placed 
in  one  of  the  later  years  of  the  course,  it  is  probable  that  not 
more  than  15  per  cent  of  all  the  pupils  during  any  one  year 
have  any  opportunity  to  take  chemistry.  The  actual  number, 
therefore,  is,  on  the  whole,  encouraging.  Attention  may  be 
called  in  passing  to  the  peculiarities,  either  in  the  opportunities 
for  taking  chemistry,  or  in  the  way  in  which  advantage  is  taken 
of  these  opportunities,  or  both,  in  different  parts  of  the  country. 
The  percentages  are  9.39  in  the  North  Atlantic  States,  12.22 
in  the  Western  States,  7.58  in  the  North  Central  States. 

The  struggle  for  rank  may  be  said  to  have  been  won  also,  but 
by  a  moral  victory.  The  opponents  are  defeated,  but  it  may  be 
doubted  whether  they  are  convinced.  They  cover  The  struggle 
their  retreat  by  the  statement  that  the  scientific  for  Rank, 
course  is  possibly  of  equal  value  with  the  classical,  but  the 
training  which  it  gives  is  different.  On  this  ground  they  fre- 
quently would  refuse  the  granting  of  the  degree  of  A.B.  to  the 
graduates  of  such  a  course.  Unquestionably  the  sciences  have 
been  at  a  disadvantage  on  account  of  their  lack  of  that  prestige 
which  three  hundred  years  of  continuous  employment  have 
given  to  the  older  subjects.  But,  putting  aside  all  prejudice, 
there  is  perhaps  still  some  ground  for  reserve  in  answering  the 
question  whether  science  has  actually  fulfilled  its  promises. 


22  INTRODUCTION 

That  its  present  average  efficiency  is  far  below  its  possible  best, 
no  one  can  doubt.  So  far  as  the  feeling  of  which  we  have 
spoken  is  due  to  a  distrust  of  science  at  its  best,  the  question 
has  already  been  disposed  of  in  the  first  section  of  this  chapter. 
So  far  as  it  expresses  a  lack  of  confidence  in  science,  and  par- 
ticularly in  chemistry  as  it  is,  some  further  inquiry  into  the 
question  will  be  proper  in  this  place,  and  before  we  pass  to 
the  discussion  of  the  means  which  in  many  schools  at  least 
have  enabled  it  to  reach  the  best. 

There  are  unquestionably  some  things  which  diminish  the 

effectiveness   of  chemistry   as  a   means  of  instruction  in  our 

schools.     The  first  of  these  is  a  lack  of  organized 

withwhich     instruction  in   scientific  matters   running   through 

Chemistry  every  year  of  school  work,  from  the  first  to  the 
Contends. 

last.     The  pupils  have  not  been  brought  up  to  the 

study  of  nature  and  physical  science  by  personal  handling  of 
the  objects  with  which  these  deal,  and  consequently  their  ability 
to  get  the  best  out  of  the  subject  is  hampered  because  their 
capacity  to  employ  the  means  of  study  has  become  partially 
atrophied  by  disuse. 

This  state  of  affairs  is  certainly  being  remedied,  but  that  the 

improved  conditions  have  yet  had  time  to  affect  the  average 

teaching  in  chemistry,  may  be  doubted.     Contrast  this  with  the 

f      custom  of  continuously   employing  the  methods  of  language 

/      study  from  the  earliest  years,  which  every  child  has  acquired, 

and  the  disadvantage  under  which  chemistry  labours  is  at  once 

apparent. 

Still  another  impediment  may  be  found  in  the  instruction  in 
chemistry  in  the  higher  institutions  which  are  intrusted  with 
Defects  in  the  tne  ^u^  °*  trammg  tne  teachers.  As  before,  we  are 
Means  af-  speaking  of  the  average  and  not  of  the  best.  It  has 
Training*  been  asserted,  and  with  justice,  that  the  greater 
of  Teachers.  part  of  tm's  training  is  essentially  non-scientific  in 
its  tendency.  The  instruction  is  too  dogmatic,  and  books  are 
too  largely  the  reliance  of  the  instructors.  The  pupils  are  not 
disciplined  in  the  methods  of  observation  and  investigation, 


INTRODUCTION  23 

and  there  is  too  much  speculation  substituted  for  the  much 
more  conservative  theorizing  and  explanation  which  are  alone 
permissible.  The  pupils  are  not  brought  in  contact  with  the 
spirit  of  the  subject  by  the  study  of  the  original  sources  and  the 
memoirs  of  investigators,  and,  above  all,  they  are  scarcely  ever 
called  upon  to  perform  any  original  investigation,  no  matter 
how  simple,  on  their  own  account.  Such  instruction  can 
never  transfuse  into  the  minds  of  the  pupils  any  notion  of  the 
spirit  of  the  subject.  Take,  for  example,  the  conventional  course 
in  chemistry.  Even  if  the  subject  is  studied  for  two  or  three 
years,  which  occurs  in  the  preparation  of  a  small  minority  only 
of  the  prospective  teachers  in  secondary  schools,  the  time  is 
largely  occupied  with  quantitative  and  qualitative  analysis,  sub- 
jects which  should  play  a  subordinate  part  in  the  preparation  of 
the  teacher,  unless  he'  has  ample  time  at  his  disposal.  It  is 
general  chemistry  that  he  must  knqw^and  instruction  in  these 
other  branches  not  only  contributes  little  to  his  knowledge  of 
the  main  trunk,  but  even  diverts  his  attention  from  it.  Com- 
parison with  the  training  given  in  languages  and  mathematics 
shows  that,  although  it  may  be  easy  to  point  out  defects,  the 
preparation  is,  after  all,  much  more  thorough  in  the  directions 
in  which  the  work  of  teaching  in  the  secondary  school  makes 
the  heaviest  demands.' 

The  results  of  faulty  training  of  the  teacher  are  more  serious 
in  science  than  in  language.  As  Professor  Macgregor  says, 
"  In  the  making  of  linguistic  knowledge,  a  pupil  under  an 
incompetent  teacher  does  not  stick  fast.  He  has  the  experi- 
ence of  his  childhood  to  help  him,  is  capable  of  exercising  the 
knowledge-making  power  without  the  teacher's  aid,  on  the 
familiar  material  which  language  affords,  and  in  his  effort  to 
make  progress,  cannot  help  exercising  it  to  a  greater  or  less 
extent.  Let  me  draw  special  attention  to  this  point ;  for  the 
fact  that  in  the  study  of  language,  exercise  of  the  knowledge- 
making  power  is  not  only  possible,  but  in  a  large  measure 
unavoidable,  even  under  an  incompetent  teacher,  gives  to  lan- 
guage study  a  great  advantage  over  science  study,  as  a  means 


24  INTRODUCTION 

of  discipline  in  all  educational  institutions,  but  especially  in 
those  of  lower  grade,  in  which,  owing  to  their  large  number, 
the  difficulty  of*  securing  competent  teachers  is  especially 
great." 

Still  another  cause  of  diminished  effectiveness  in  chemistry 
teaching  is  the  lack  of  unity  in  the  aims  and  methods  of  the 
La  k  of  unity  teacners-  This  is  the  result  of  the  existence  of  the 
in  Aim  and  same  fault  in  the  work  of  the  higher  institutions. 
Some  elementary  courses  in  chemistry  are  devoted 
largely  to  analysis.  In  others,  the  discourse  is  mainly  of  atoms. 
These,  instead  of  being  employed  as  conceptions  rather  than 
facts,  are  described  with  such  realism  that  the  study  of  the  sub- 
ject by  experiment  is  pressed  into  the  background,  either 
actually  or  in  the  estimation  odf  the  pupils.  This  lack  of  unity 
is  so  notorious  that  when,  a  few  years  ago,  a  set  of  educational 
conferences  was  called  at  Columbia  University,  no  conference 
on  science  was  held.  It  was  considered  that  the  opinions  of  its 
advocates  were  so  unsettled  that  the  colleges  had  no  basis  on 
which  to  fix  definite  requirements  in  science  at  all.  We  have  but 
to  look  at  text-books  on  chemistry  in  order  to  see  that,  although 
they  are  all  labelled  chemistry,  their  content  and  spirit  differ 
widely.  We  have  but  to  compare  them  with  the  standard  trea- 
tises on  languages  and  mathematics  to  see  how  much  greater 
the  unity  is  which  has  been  reached  in  these  subjects. 

In  enumerating  the  disadvantages  under  which  the  teacher 
labours  in  fitting  chemistry  for  a  place  in  the  curriculum,  we 

must  note  that  not  the  least  of  these  is  the  difficulty 
The  Intrinsic 

Difficulty  of     of  the  subject  itself.      To   quote   Professor   Mac- 

the  Science.      gregor  agam>  «A  difficulty  with  which  the  sound 

teaching  of  science  has  met,  arises  from  the  complex  character 

of  its  subject-matter.     To  compare  different  usages  of  words, 

for  example,  one  has  but  to  turn  over  the  leaves  of  a  book  ;  to 

compare  instances  of  the  occurrence  of  natural  phenomena,  the 

phenomena  must  be  watched  for  or  reproduced  under  varying 

.    conditions."     Or  again,  as  Professor  Cooley  says,  "Phenomena 

;   are  the  symbols  in  which  truths  are  written,  but  phenomena 


INTRODUCTION  2$ 

abound  in  superficial  likenesses,  obscure  differences  and  decep- 
tive analogies.  A  correct  translation  of  this  language  requires 
keen  perception,  accurate  judgment  and  crystalline  forms  of 
expression.  "  It  is  undoubtedly  harder  to  carry  the  subject  to 
a  depth  corresponding  to  that  which  would  be  reached  in 
French  or  Latin,  or  to  master  it  with  equal  thoroughness. 

The  case  is  often  made  worse  by  putting  chemistry  before 
physics  in  one  of  the  earlier  years  in  the  secondary  school. 
The  highest  benefits  can  be  got  from  its  study  only  when  the 

time  comes  at  which,  as  Professor  Nicholas  Murray 

~     ,  .  j    r        ^  f  Trivial  Nature 

Butler,  in  attempting  to  define  the  stages  of  psy-   Of  much  School 


chological  development  and  ascertain  their  corre-  ., 

Chemistry. 
spondences  with    the    stages   in   our   educational 

system,  says,  the  soul  "  demands  new  and  more  difficult  prob- 
lems to  occupy  it  and  absorb  its  activities."  As  we  hope  to 
show  later,  the  organization  of  the  teaching  of  chemistry  at  its 
average  is  in  need  of  very  great  improvement  before  adequate 
benefit  can  be  conferred  by  it,  even  in  the  fourth  year  of  the 
secondary  school.  At  present  much  time  is  wasted  on  the 
study  of  superficial  aspects  of  this  science,  when  the  same  time 
devoted  to  languages  or  mathematics  might  have  gone  much 
deeper  and  been  educationally  much  more  effective.  Much 
testimony  is  available  to  prove  that  the  chemistry  work  in 
the  average  school  is  not  a  trial  worthy  of  the  powers  of  the 
pupils.  To  use  the  expressive  phrase  of  a  friend  of  mine, 
"There  is  too  much  chicken-feed  chemistry  occupying  time 
that  might  have  been  devoted  to  the  giving  of  solid  nourish- 
ment." One  needs  but  to  visit  a  number  of  schools  to  see  that 
there  is  truth  in  this  statement.  I  have  seen  work  in  English 
being  done  by  the  freshmen  of  a  high  school  which  showed  a 
surprising  grasp  of  the  more  abstract  aspects  of  rhetoric  and  an 
ability  to  handle  problems  of  literature  in  a  wonderfully  effec- 
tive manner,  while  the  same  pupils  in  the  next  year  were  putter- 
ing with  a  kind  of  chemistry  which,  it  may  be  said  without 
exaggeration,  would  not  have  over-taxed  the  ability  of  a  reason- 
ably intelligent  infant  if  its  physical  development  had  permitted 


26  INTRODUCTION 

it  to  attempt  the  work.  A  mode  of  study  in  a  science  which 
does  not  take  full  advantage  of  the  knowledge-making  power 
which  it  can  call  forth,  not  only  largely  wastes  the  time  it  occu- 
pies  and  discredits  the  science  itself,  but  diminishes  the  effi- 
ciency  of  the  whole  curriculum  of  instruction.  There  is  reason 
to  fear  that  chemistry  has  gained  admission  before  the  means  of 
using  it  most  effectively  have  become  widely  known. 

The  work  in  science  is  also  frequently  hampered  by  the  atti- 
tude of  the  authorities  of  the  school,  who  may  not  be  as  fully 
Some  Other  convinced  of  its  value  as  their  introduction  of  the 
Hindrances,  subject  into  the  curriculum  would  lead  us  to  ex- 
pect. They  are  apt  to  promote  pupils  who  have  neglected 
scientific  work,  provided  they  have  done  well  in  other  studies. 
They  are  apt  also  to  appease  the  clamour  for  representation 
of  science  in  their  school  by  assigning  classes  in  chemistry 
to  teachers  who  have  had  almost  no  preparation  in  the  subject, 
instead  of  delaying  its  introduction  until  they  can  afford  to  obtain 
a  properly  prepared  instructor.  They  are  prone  to  load  four  or 
five  sciences  on  one  teacher,  regardless  of  the  utter  impossibility 
of  organizing  good  laboratory  instruction  under  such  circum- 
stances, even  if  the  preparation  of  the  teacher  should,  by  a 
miracle,  be  not  unequal  to  the  task.  They  cut  the  day  into 
equal  and  often  very  brief  periods,  as  if  mechanical  adjustment 
of  time  were  everything,  and  the  essential  differences  between 
laboratory  work  and  class  work,  in  respect  to  the  value  which 
each  can  get  out  of  thirty  or  forty  minutes,  were  nothing. 

To  secure  instruction  in  science  of  effectiveness  equal  to  that 
in  other  subjects,  and  to  wrest  from  it  the  benefits  which  it  ad- 
mittedly can  confer,  we  must  have  continuous  in- 
Summary. 

struction  in  science,  beginning  with  nature  study 

in  the  elementary  schools ;  we  must  have  at  the  other  end  im- 
provement in  the  chemical  curricula  in  the  highest  institutions 
\vhich  furnish  the  teachers ;  we  must  have  unanimity,  or  some 
approach  to  it,  in  regard  to  the  aims  and  methods  of  secondary 
school  chemistry  ;  and  we  must  work  out  the  detailed  organiza- 
tion of  the  teaching  of  chemistry  more  fully.  When  these  things 


INTRODUCTION  2/ 

have  been  accomplished,  proper  respect  for  the  subject  at  the 
hands  of  all  educational  authorities  will  come  of  itself.  At 
present  the  average  instruction  in  chemistry  does  not  even  re- 
motely approach,  in  the  benefits  which  it  gives,  the  best  that 
can  be  given  or  is  given.  When  the  difficulties  we  have 
enumerated  have  been  removed,  or  considerably  reduced,  we 
may  confidently  expect  that  chemistry,  at  its  average,  will 
worthily  fulfil  the  hopes  which  the  reasons  given  for  its  study 
awaken.  It  is  in  the  earnest  hope  of  contributing  something, 
however  little,  to  the  attainment  of  this  end  by  bringing  to- 
gether the  opinions  of  all  authorities  on  the  teaching  of  chem- 
istry in  secondary  schools  that  the  following  chapters  have  been 
written. 


CHAPTER   II 

CHEMISTRY  IN   THE    CURRICULUM 
REFERENCES. 

Report  of  the  Committee  of  Ten  of  the  National  Educational  Associa- 
tion. Washington,  D.C.,  U.  S.  Bureau  of  Education.  1893.  PP-  ri7-I23- 

Woodhull,  J.  F.  Sequence  of  Sciences  in  the  Secondary  School 
Curriculum.  High  School  Bulletin  No.  7.  Albany,  N.  Y.,  The  Univer- 
sity of  the  State  of  New  York.  Pp.  516-523. 

THE  sequence  of  chemistry  with  reference  to  other  subjects 
and  the  year  in  which  it  shall  be  placed  are  questions  of  great 
importance,  since  they  affect  profoundly  the  manner  of  the 
instruction  and  the  amount  that  can  be  accomplished.  This 
question  can  hardly  be  said  to  arise  except  in  connection  with 
the  sciences.  In  the  case  of  Greek  the  doubt  lies  between 
the  second  and  third  years.  In  English,  Latin,  or  mathemat- 
ics the  first  year  is  the  natural  place  for  the  beginning  course. 
In  science,  however,  we  have  a  choice  of  five  or  six  distinct 
subjects  which  may  conceivably  be  taught  in  any  sequence, 
each  in  any  year.  Observation  of  schools  shows  that  this 
freedom  is  made  use  of  to  the  fullest  extent.  Not  to  occupy 
too  much  space  with  the  discussion  we  may  confine  ourselves 
to  the  question  of  the  order  in  the  case  of  chemistry  and  phys- 
ics, and  whether  the  physical  sciences  should  be  placed  in  the 
earlier  or  later  years  of  the  high  school  eourse.  Even  with  this 
restriction,  there  is  not  the  slightest  approach  to  unanimity  on 
either  of  these  questions,  either  in  the  opinions  of  school-men 
themselves,  or  in  the  practice  of  the  schools.  Something  more 
final  than  the  opinion  of  the  individual  teacher  is  required, 
since,  if  he  is  interested  in  securing  the  best  work  from  his 
pupils  in  chemistry,  he  will  naturally  prefer  to  secure  a  place 


CHEMISTRY  IN   THE   CURRICULUM  29 

V 

in  the  fourth  year  of  the  school  for  this  work.  Several  of 
the  points  involved  in  the  discussion  of  theje  questions  have 
so  important  a  bearing  on  the  teaching  of  chemistry  that  we 
shall  be  justified  in  devoting  some  space  to  their  consideration. 

I.     The  Precedence  of  Physics. 

a.  The  Report  of  the  Committee  of  Ten :  —  In  the  report  of  the 
Committee  of  Ten  perhaps  the  point  which  excited  most  dis- 
cussion was  the  decision  which  they  reached,  that 
chemistry  should  be  taught  before  physics.  It  is  Physics  £. 
undoubtedly  conceded  by  all  that  the  logical  order  *ore  Chem- 
is  just  the  reverse  of  this.  The  minority  report  of 
Professor  Waggener  states,  with  considerable  clearness,  the 
reasons  which  lead  him  to  dissent  from  this  part  of  the  re- 
port. In  brief,  these  were  as  follows :  Since  in  training  the 
pupil  to  make  accurate  observations  and  to  draw  safe  infer- 
ences, the  more  simple  subject-matter  should  precede  the  less 
simple,  and  that  which  is  more  obvious  to  the  senses  that  which 
is  less  so,  and  since  that  which  derives  more  abundant  material 
for  illustration  and  application  from  the  experiences  of  every- 
day life  will  form  a  better  starting  point,  physics  seems  to  be 
indicated  as  the  natural  precursor  of  chemistry.  He  points  out 
that  a  great  part  of  physics  relates  to  phenomena  wherein  the 
bodies  concerned  and  their  behaviour  are  directly  perceptible  to 
the  senses  at  every  stage  of  the  experiment.  The  first  results 
thus  ^ome  from  direct  perception  rather  than  by  inference, 
and  upon  such  phenomena  the  power  of  making  inferences 
should*  first  be  trained.  The  behaviour  of  parts  of  matter  con- 
cerned in  chemical  changes,  on  the  other  hand,  is  inferred,  not 
observed ;  and  the  conceptions  we  form  of  it  are  less  simple 
than  those  of  molecular  physics,  since  it  involves  a  redistribu- 
tion of  more  than  one  kind  of  matter,  and  the  forces  in  obedi- 
ence to  which  this  takes  place  are  much  more  complex  in  the 
matter  of  selection  and  direction  than  cohesion.  "  The  ra- 
tional study  of  chemical  phenomena  is  therefore  of  a  higher 
order  of  difficulty  than  those  of  physics,  — certainly  than  those  of 


30  CHEMISTRY  IN  THE   CURRICULUM 

molecular  physics,  a  portion  of  the  subject  to  which  the  work  of 
the  high  school  is  largely  directed."  Finally  he  points  out  that 
chemical  theory  depends  for  rationalization  so  completely  upon 
an  intelligent  conception  of  its  many  and  close  relations  to 
physical  laws  that  previous  training  in  the  measurement  of  the 
fundamental  physical  constants  would  seem  to  be  indispensable. 

b.  Observations  in  Chemistry  a  Study  of  Physical  Properties : 
—  It  appears  to  me  that  the  dependence  of  chemistry  upon 
physical  conceptions  and  phenomena  might  fitly  have  been 
emphasized  much  more  strongly.  I  think  that  a  closer  exam- 
ination of  the  features  of  chemical  experimentation  will  show 
this,  and  will  incidentally  point  out  one  of  the  directions  in 
which  much  of  the  teacher's  effort  may  be  fruitfully  spent. 

When  any  chemical  operation  is  to  be  carried  out,  its  suc- 
cess invariably  depends  upon  attention  to  matters  belonging 

.   strictly  to  the  domain  of  physics.     Thus,  if  it  be  a 
Physical  Basis  / 

of  Chemical  question  of  dissolving  a  salt  in  water,  the  process 
p  a  on'  will  take  a  limitless  time  if  the  solid  is  permitted  to 
rest  at  the  bottom  of  the  vessel,  along  with  the  part  of  the  solu- 
tion which  is  slowly  becoming  more  concentrated.  Yet  it  is 
seldom  that  a  pupil  will  spontaneously  hasten  the  process  by 
mixing  or  agitation.  Again,  when  a  gas  is  to  be  generated 
and  collected  over  water,  the  filling  and  inversion  of  the  jar 
of  water  and  the  displacement  of  the  water  by  the  gas  all  in- 
volve many  physical  questions.  In  more  difficult  experiments, 
particularly  those  connected  with  the  determination  of  the 
molecular  weight  of  chemical  substances  by  one  of  the  many 
simplified  methods  which  may  now  be  used  in  any  high  school, 
physical  principles  (vapour  tension,  laws  of  gases,  adjustment  of 
pressure  before  volume  measurement,  etc.)  are  almost  the  sole 
things  to  be  considered. 

A  little  reflection  will  show  in  a  manner  still  more  striking 
how.  even  in  the  study  of  the  simplest  chemical  changes,  the 
interpretation  of  the  result  depends  upon  a  knowledge  of  physics. 
If  the  problem  be  to  ascertain  the  effect  of  heating  upon  some 
body,  the  pupil  may  observe  all  that  takes  place,  but,  without  a 


CHEMISTRY  IN   THE   CURRICULUM  31 

rapid  concurrent  interpretation  of  each  feature  as  it  presents 
itself  by  reference  to  physical  principles,   the  experiment  will 

lead  to  no  correct  conclusions  whatever.     The  sub- 

Fnysical  Basis 

stance  may  melt,  and  the  pupil  must  ascertain  of  Chemical 
whether  this  is  simply  a  physical  change,  or  whether  Observation- 
it  involves  chemical  change  also.  The  substance  may  boil, 
or  appear  to  do  so.  The  pupil  must  be  in  a  position  to  dis- 
tinguish between  boiling  and  decomposition  accompanied  by 
the  production  of  a  gas,  for  example,  by  the  fact  that  the  removal 
of  the  source  of  heat  interrupts  boiling,  but  usually  does  not  so 
promptly  affect  the  progress  of  decomposition.  In  heating 
ammonium  nitrate 1  we  have  an  excellent  illustration  of  a  multi- 
plicity of  things  which  require  physical  explanation.  The  ex- 
periment is  full  of  points,  such  as  the  apparent  violence  of  the 
boiling  while  the  bubbles  of  gas  rising  in  the  bottle  succeed 
one  another  but  slowly,  and  the  cloud  of  smoke  which  some- 
times accompanies  the  gaseous  materials  and  passes  successfully 
through  the  water,  all  of  which  require  careful  consideration  of 
the  physical  properties  of  matter  for  their  explanation. 

Again,  suppose  that  the  problem  before  the  pupil  is  the  ex- 
amination of  the  action  of  various  metals  upon  concentrated 
hydrochloric  acid,  and  that  he  is  instructed  merely  Furt]ier illus. 
in  the  method  of  bringing  the  materials  together,  and  tration. 
is  expected  to  observe  what  follows  for  himself.  He  must  have 
recourse  to  physics  to  ascertain  whether  the  effect  following  the 
introduction  of  zinc  is  boiling,  and  consists  in  the  evolution  of 
steam,  or  is  produced  by  the  development  of  hydrogen.  Usually 
his  first  thought  is  to  attribute  the  effect  to  boiling,  and  indeed 
the  reasoning  of  the  observer  must  frequently  consist  in  draw- 
ing a  trial  conclusion,  and  then  testing  it  by  known  physical 
facts.  Again,  when  the  copper  is  introduced  into  the  acid  no 
action  takes  place.  But  when  the  mixture  is  warmed,  bubbles 
of  vapour  are  given  up  apparently  from  the  neighbourhood  of  the 
copper,  and  the  pupil  is  likely  now  to  conclude  that  hydrogen  is 

1  This  illustration  is  fully  discussed  by  R.  P.  Williams.    New  England 
Association  of  Chemistry  Teachers,  Report  of  Fifth  Meeting  (1899),  4- 


32  CHEMISTRY  IN  THE   CURRICULUM 

being  formed.  This  conclusion  must  be  suspended,  however, 
when  he  realizes  that  the  liquid  being  heated  is  a  strong  solu- 
tion of  a  gas.  He  must,  therefore,  either  ascertain  whether  the 
escaping  vapour  contains  hydrogen,  or  indirectly,  by  looking  for 
the  blue  colour  of  a  salt  of  copper,  recognise  that  there  has  really 
been  no  formation  of  such  a  salt,  and  therefore  there  can  have 
been  no  evolution  of  hydrogen. 

It  is  hardly  necessary  to  add  that  when  parts  of  physics  have 
to  be  drawn  upon  wholesale,  as  the  kinetic  theory  of  gases  in 
explaining  Avogadro's  hypothesis  and  its  applications,  or  the 
properties  and  employment  of  electricity  in  experiments  in  elec- 
trolysis, a  previous  acquaintance  with  dynamics  and  electricity 
is  of  the  utmost  value.  In  the  contrary  case,  the  extreme  un- 
familiarity  of  the  whole  thing  interposes  a  tremendous  drag  on 
the  progress  in  chemistry. 

A  careful  consideration  of  any  chemical  experiment,  even  the 
simplest,  thus  reveals  the  fact  that  an  intimate  knowledge  of  the 
physical  properties  of  matter  is  required  in  carrying  it  out  suc- 
cessfully, and  in  interpreting  the  results.  This  knowledge  of 
physics  must  be  even  more  intimate  than  that  demanded  of  the 
pupil  of  physics  himself,  for  in  the  case  of  the  latter  the  work  is 
outlined  in  such  a  way  that  the  subject  under  investigation  and 
the  method  are  both  known  beforehand.  In  a  chemical  experi- 
ment, the  physical  phenomena  turn  up  without  warning,  and  the 
pupil  must  identify  them  instantly  and  understand  their  whole 
bearing  if  the  conclusion  is  to  be  otherwise  than  doubtful  or 
hazy.  In  fact,  the  matters  of  immediate  observation  in  a  chemi- 
cal experiment  are  all  physical,  and  the  data  derived  from  these 
depend  upon  physical  knowledge,  and  thus  everything  but  the 
final  conclusion  is  physical  and  not  chemical. 

It  has  been  remarked  that  "  each  chemical  experiment  is  a 

question  put  to  nature,  and  forethought  and  care  are 

nomena  the  *~  necessary  in  putting  the  question,  and  study  and 

Language  of  reflection  in  interpreting  the  answer."  In  view  of 
Chemistry. 

the  above  we  note  that  the  chemical  question  has 

to  be  put  in  a  strange  language  (namely,  by  physical  methods), 


CHEMISTRY  IN  THE   CURRICULUM  33 

and  the  answer  is  returned  in  the  same  foreign  language.  This 
language  must  therefore  be  mastered  before  the  question  can  be 
put  or  the  reply  understood.  The  education  of  a  chemist  con- 
sists largely  in  acquiring  a  colloquial  knowledge  of  this  language. 

c.  The  Conclusion  :  —  Whether  chemistry  or  physics  should 
come  first  is  thus  seen  to  be  an  idle  question.  Physics  jpusj; 
come  first.  The  question  really  is  whether  it  is  better  to  furnish 
a  systematic  knowledge  of  physics  during  the  previous  year,  or 
leave  it  to  be  picked  up  as  it  is  presented,  hap-hazard,  in  the 
course  of  chemical  work.  When  the  question  is  put  in  this 
form,  there  can  be  little  doubt  in  regard  to  the  answer.  It  is 
true  that  the  course  in  physics  will  probably  not  deal  in  any 
sufficient  detail  with  some  of  the  phenomena  most  intimately 
connected  with  chemistry.  But  the  facility  with  which  the  pupil 
who  has  surveyed  the  whole  ground  in  outline  will  acquire  fur- 
ther knowledge  of  the  same  kind,  will  be  incomparably  greater 
than  that  of  the  pupil  who  has  no  "  apperceptive  mass"  in 
which  the  fragmentary  facts  noted  in  the  course  of  chemical 
work  may  be  absorbed. 

It  is  evident  that  when  chemistry  precedes  physics,  the  former 
subject  will  furnish  a  more  valuable  introduction  to  the  latter 
than  in  recent  discussion  has  been  generally  admitted.  A 
teacher  of  chemistry,  whether  he  will  or  not,  is  bound  to  fur- 
nish some  instruction  in  physics,  and  the  result,  while  it  must 
necessarily  be  unsystematic,  will  nevertheless  assist  materially 
in  the  subsequent  study  of  the  same  thing.  The  study  of  either 
subject  is  bound  to  hasten  the  process  of  acquiring  the  other, 
but  the  precedence  of  physics  is  the  more  economical  arrange- 
ment, since  it  will  but  little  diminish  the  speed  with  which 
physics  may  be  acquired,  while  greatly  accelerating  the  prog- 
ress of  the  pupil  in  chemistry. 

II.     Arguments  in  Favour  of  the  Precedence  of  Chemistry. 

The  decision  of  the  Committee  of  Ten  seems  to  have  been 
based  finally  upon  the  consideration  that  the  greatest  amount 
of  mathematical  training  possible  should  be  secured  before  the 

3 


34  CHEMISTRY  IN  THE  CURRICULUM 

pupils  enter  upon  the  study  of  physics.  Authorities  on  this 
subject,  however,  do  not  seem  by  any  means  to  be  unani- 
Physics  and  mous  m  thinking  that  a  course  in  advanced  algebra 
Mathematics,  and  solid  geometry  are  really  indispensable  prerequi- 
sites. In  algebra  the  solution  of  simple  equations  is  usually 
considered  sufficient,  while  in  geometry  the  determination  of 
the  area  of  the  parallelogram  and  circle,  and  the  volumes  of  the 
sphere  and  cylinder  can  easily  be  given  by  the  teacher  of  phys- 
ics, and  thus  the  postponement  of  the  work  for  the  whole  year 
may  be  avoided.  It  is  probable  that  the  Committee  of  Ten 
was  really  thinking  of  the  value  of  the  general  discipline  which 
these  subjects  would  undoubtedly  confer,  rather  than  of  any 
considerable  percentage  of  the  subjects  themselves  which  would 
be  required  for  the  service  of  the  teacher  of  physics. 

It  is  frequently  maintained  that  chemistry  may  and  should  be 
taught  more  simply  than  physics.  This  is  an  insidious  argu- 
ment. Every  subject  should  be  taught  simply,  if 
simpler  than  by  the  term  we  mean  that  it  should  be  so  carefully 
Physics?  related  at  every  step  to  the  previous  knowledge  of 
the  pupil  that  over-strenuous  effort  on  the  one  hand,  and  obscu- 
rity on  the  other,  are  avoided.  But,  in  many  cases,  the  simplifica- 
tion which  makes  chemistry  an  easy  study  is  not  of  this  kind. 
It  involves  not  the  careful  bridging  of  all  gaps  and  rational  ap- 
proach to  conquest  of  all  difficulties,  but  rather  the  mutilation 
of  the  subject  and  the  removal  of  most  of  the  science  along  with 
the  difficulties.  For  example,  in  studying  the  action  of  a  metal 
upon  hydrochloric  acid,  we  have  seen  that  an  intimate  knowl- 
edge of  the  physical  properties  of  the  materials  is  required. 
But  we  may  "simplify"  the  experiment,  heading  it  "  Standard 
method  of  making  hydrogen,"  and  direct  the  pupil  to  place 
zinc  in  hydrochloric  acid.  By  this  arrangement,  as  he  already 
knows  that  hydrogen  is  a  gas,  no  close  observation,  no  knowl- 
edge of  physics,  and  no  reasoning  are  demanded  of  him.  The 
whole  pith  of  the  exercise  has  been  removed  as  an  incident  of 
the  simplification  however.  Chemistry  can  thus  be  reduced  to 
a  series  of  cook-book  receipts,  and  all  difficulties  may  disap- 


CHEMISTRY  IN  THE   CURRICULUM  3$ 

pear  simultaneously  with  the  removal  of  all  the  discipline  which 
chemistry  is  most  fitted  to  impart.  A  large  part  of  the  work 
may  be  arranged  so  as  to  consist  in  the  formation  of  precipi- 
tates. Here  the  same  set  of  physical  phenomena  is  repeated 
time  after  time  without  variation,  and  the  chemical  conclusions, 
namely,  that  a  certain  substance  is  or  is  not  formed,  and  if 
formed  is  black  or  red,  as  the  case  may  be,  may  be  drawn  with- 
out the  pupil  once  realizing  what  the  physical  conditions  are 
that  make  this  possible. 

When  the  work  has  thus  been  conventionalized,  so  to  speak, 
it  ceases  to  deserve  the  name  of  chemistry.  It  has  variously 
been  designated  as  " cookery  "  and  "test-tubing."  Yet  scorn 
does  not  seem  to  have  much  effect  in  appreciably  reducing  the 
amount  of  this  kind  of  mechanical  work.  There  are  still  some 
who  seem  to  think  that  anything  which  deals  with  chemical  ma- 
terials and  uses  chemical  terms  is  in  some  measure  chemistry. 
There  are  laboratory  manuals  that  can  be  used  with  delightful 
facility  by  the  largest  class,  and  with  the  least  amount  of  super- 
vision, which  furnish  the  pupil  with  little  work  that  is  not  of  this 
description. 

The  mention  of  text-books  reminds  us,  that  the  fact  that  high 
school  books  on  chemistry  appear  to  be  simpler  than  those  on 
physics,  has  been  used  as  an  additional  support  of  the  argument 
that  chemistry  is  intended  to  precede  physics.  This  really  in- 
volves the  question  of  the  choice  of  a  text-book,  which  we  shall 
discuss  in  another  chapter.  It  may  be  remarked,  however, 
that  chemistry  books  are  not  as  simple  as  they  seem.  Many 
works  intended  for  high  school  use  are  filled  with  graphic  form- 
ulae. I  know  no  subject  which  is  found  more  difficult  by  the 
beginner  than  the  comprehension  of  the  way  in  which  a 
graphic  formula  represents  the  chemical  properties  of  a  sub- 
stance. The  books  I  refer  to  seem  to  realize  this,  for  they 
make  no  attempt  to  explain  the  formulae  they  employ.  Per- 
haps they  leave  that  task  to  the  teacher.  The  usual  result 
seems  to  be,  however,  that  the  formulae  are  memorized,  and  are 
highly  prized  as  the  subjects  of  examination  questions.  If  the 


36  CHEMISTRY  IN   THE    CURRICULUM 

laws  and  formulae  found  in  works  of  physics  were  to  be  memor- 
ized also,  that  subject  might  rival  chemistry,  if  not  excel  it,  in 
simplicity.  The  teacher  is  not  compelled  to  confine  himself  to 
the  most  trivial  treatment  of  chemistry.  Avogadro's  hypothesis 
and  its  consequences,  involving  as  it  does  the  determination  of 
molecular  weights,  atomic  weights,  valency,  and  the  construc- 
tion of  formulae  and  equations,  is  the  most  fundamental  prin- 
ciple in  chemistry,  and  will  usually  be  found  as  difficult  a  subject 
as  anything  in  elementary  physics.  Professor  van  't  Hoff,  in  a 
recent  lecture,  stated  that  as  a  student  he  never  had  understood 
the  application  of  this  hypothesis,  and  that  he  learned  it  only 
when  he  became  an  instructor  in  chemistry. 

The  argument  that  the  manipulation  in  chemistry  is  simpler 
than  in  physics,  and  therefore  fitted  to  precede  the  latter,  is 
based  upon  the  same  assumption  as  before.  If  we 
Manipulation  emasculate  the  subject  sufficiently,  we  can  make  it 
easier  than  simpler  than  any  other  subject  that  may  be  named, 
Physical?  kut  •£  ^e  ^eac]1jng  jn  chemistry  attempts  to  include 
the  fundamental  principles  of  the  science,  as  the  teaching  in 
physics  does,  it  need  not  suffer  from  lack  of  experiments  requir- 
ing skill,  patience,  and  knowledge.  The  determination  of  molec- 
ular weights,  and  the  measurement  of  combining  weights,  are 
the  most  fundamental  things  in  elementary  chemistry.  They 
are  not,  by  any  means,  beyond  the  skill  of  the  high  school 
pupil,  or  the  equipment  of  the  high  school  laboratory,  but  they 
are  not  to  be  classed  in  simplicity  with  naming  salts,  or  dis- 
tinguishing '  silver,'  '  lead/  and  '  mercury  '  by  the  use  of  hy- 
drochloric acid  and  ammonia. 

Nor  need  we  have  recourse  to  experiments  of  a  quantitative 
nature  to  furnish  instances  of  difficulty  in  chemical  work.  The 
pupil  in  chemistry  is  confronted  with  one  difficulty  in  every  ex- 
periment, which  it  seems  to  me  is  not  met  with  in  the  same 
degree  in  any  of  the  other  sciences.  The  difficulty  rests  on  the 
fact  that  before  observing,  he  has  himself  to  produce  that  which 
he  is  to  study.  There  is  doubtless  important  training  for  the 
pupil  who  is  called  upon  to  examine  a  cockroach  minutely,  and 


CHEMISTRY  IN  THE   CURRICULUM  37 

report  upon  the  number,  location,  and  kinds  of  its  appendages. 
But  if  he  had  to  create  the  cockroach  by  a  definite  method  of 
procedure,  it  is  likely  that  his  observations  would  less  exactly 
describe  the  standard  animal  than  they  do.  In  chemical  work 
almost  every  experiment  will  show  varying  results  in  the  hands 
of  different  students,  all  working  by  the  same  directions.  Some 
will  use  concentrated  sulphuric  acid  or  pure  zinc,  and  so  fail  in 
obtaining  hydrogen  ;  a  solution  may  be  applied  in  too  concen- 
trated a  form,  or  too  much  may  be  used  ;  a  test-tube  may  not  have 
been  thoroughly  cleaned.  Every  teacher  knows  how  puzzling 
the  '  sports  '  are  which  the  pupil  may  produce  in  this  creative 
work.  Nor  is  carelessness  always  to  blame.  Directions  so 
minute  as  to  remove  all  possibility  of  variation  from  the  desired 
result  would  frequently  be  so  elaborate  as  to  be  impracticable. 
Successful  laboratory  work  in  chemistry  must  depend  largely  on 
the  knowledge,  forethought,  and  skill  of  the  pupil.  The  use  of 
these  is  an  essential  part  in  chemical  manipulation,  and  makes  it 
at  least  as  difficult  as  anything  in  the  other  sciences. 

III.     In  which  year  of  the  High  School  Course  shall  Chemistry 
be  taught  ? 


amount  of  work  which  can  be  given  in  a  year,  and  the 
thoroughness  with  which  it  can  be  given,  must  be  influenced 
very  greatly  by  the  general  advancement  of  the  pupil!  Prob- 
ably at  least  twice  as  much  can  be  done  in  the  fourm  year  as 
in  the  first,  on  this  account  alone.  The  necessary  absence  of 
previous  training  in  physics,  in  the  latter  case,  must  greatly  in- 
crease the  disproportion.  Every  science  cannot  secure  a  place 
in  the  fourth  year,  and  so  have  the  advantage  of  reaching  the 
pupils  who  are  most  mature  and  have  had  the  largest  prelimi- 
nary training  in  other  sciences.  The  decision  must  mainly 
depend  upon  whether  chemistry  or  some  other  science  is  to  be 
selected  for  most  elaborate  treatment.  If  physical  geography 
or  physiology  secure  the  coveted  position,  either  will  obviously 
be  benefited  greatly  by  the  fact  that  it  is  preceded  by  a  course 
in  chemistry.  The  general  tendency  in  the  secondary  schools, 


38  CHEMISTRY  IN  THE   CURRICULUM 

however,  is  undoubtedly  to  emphasize  most  strongly  the  funda- 
mental sciences,  and  to  treat  with  less  considerations  those  which 
are  developed  largely  by  the  application  of  physical  and  chemi- 
cal principles. 

It  has  indeed  been  said  that  habits  of  neatness,  care,  and 
skill  in  manipulation  cannot  be  learned  after  the  second  year  of 
Ar  umentfor  tne  n^Sn  school,  and  that  therefore  chemistry  and 
Chemistry  in  physics  should  occupy  these  two  years.  This  argu- 
irs*  ment,  however,  seems  to  assume  that  the  work  of 
the  chemist  requires  the  agility  of  the  pianist,  or  the  suppleness 
of  the  acrobat.  Surely  what  is  needed  is  rather  the  patient, 
intelligent,  and  forethoughtful  variety  of  manipulation  which  is 
favoured  by  maturity  rather  than  by  youth.  No  difficulty  seems 
to  be  found  in  training  surgeons  in  precisely  this  sort  of  way,  in 
years  much  later  than  those  just  mentioned. 

There  seems  to  be  good  ground  for  the  contention  that 
physics  and  chemistry  cannot  give  up  the  fullest  discipline  of 

which  they  are  capable  in  the  earlier  years  [  of  the 
Arguments 
forChemistry  course.      Without    mathematics,   physics   must   be 

in  Later  feeble,  and  without  physics,  the  chemistry  must  be 

considerably  restricted.  Then,  too,  the  continuous 
and  minute  supervision,  which  work  in  chemistry  requires,  must 
be  greater  the  earlier  it  appears  in  the  curriculum,  to  offset  the 
slighter  previous  knowledge  of  the  pupils.  In  practice,  how- 
ever, the  much  larger  classes  of  the  earlier  years  would  entail  a 
diminution  in  the  supervision,  rather  than  an  increase  in  it,  and 
thus  still  further  reduce  the  efficiency  of  the  work. 


1  Although  the  entrance  requirements  of  universities  should  not  be 
permitted  to  interfere  with  the  arrangement  of  the  work  of  the  secondary 
schools,  if  their  interests  conflict,  it  may  be  noted  that,  so  far  as  chemistry 
is  accepted  at  all  as  an  admission  subject,  the  work  done  in  the  first  or 
second  year  will  almost  always  satisfy  the  very  indefinite  requirement. 
The  work  outlined  by  the  University  of  the  State  of  New  York,  and  the 
questions  asked  in  their  examinations,  are  said  to  pre-suppose  fourth  year 
work.  The  requirements  of  the  Examination  Board  of  the  colleges  of 
the  Middle  States  and  Maryland,  and  those  of  one  or  two  universities  out- 
side of  this  organization  which  have  definitely  outlined  admission  work  in 
this  subject,  practically  demand  fourth  year  work. 


CHEMISTRY  IN  THE   CURRICULUM  39 

[^Perhaps  the  far-reaching  relations  of  chemistry  to  commerce 
and  industry,  the  value  of  the  discipline  which  it  affords  in  pre- 
paring for  a  business  career,  and  its  importance  in  preparation 
for  the  study  of  medicine  and  technology  are  worthy  of  notice  as 
inclining  the  schools  very  generally  to  give  it  the  most  favourable 
position  among  the  sciencesj  It  is  at  least  certain  that  many 
bodies  of  recognised  authority  incline  to  recommend  the  placing 
of  it  late  in  the  course.  The  Committee  of  Ten  (1892)  set  it  in 
the  third  year  immediately  before  physics.  The  Committee  of 
the  National  Education  Association  on  College  Entrance  Re- 
quirements (1899)  indicated  that  the  last  year  was  the  most  ap- 
propriate, and  the  University  of  the  State  of  New  York  makes 
the  same  recommendation.'  In  individual  schools  there  may  be 
good  reason  for  departing  from  this  arrangement.  Successful 
curricula  have  been  devised  in  which  the  advantage  of  prelimi- 
nary chemistry  was  secured  to  the  teachers  of  biology,  physics, 
and  physiography  without  reducing  the  opportunity  of  the  pupils 
to  secure  the  best  training  in  chemistry.  This  is  done  by  intro- 
ducing selected  parts  of  the  subject,  along  with  some  physics 
and  physical  geography,  into  a  course  in  general  science  which 
occupies  the  first  year.  The  regular  course  in  chemistry  which 
comes  later  can  only  be  benefited  by  this  arrangement.  In  a 
few  schools  a  compromise  with  the  recommendation  of  the 
Committee  of  Ten  is  effected  by  dividing  the  third  year  between 
physics  and  chemistry,  and  then  offering  a  full  course  in  both 
of  these  subjects  as  alternatives  in  the  fourth  year. 

Uniformity  in  the  arrangement  of  the  curricula  of  all  secon- 
dary schools  can  never  be  achieved,  and  is  probably  not  desir- 
able. The  chief  value  of  the  discussion  in  this  chapter  to  the 
teacher  of  chemistry  lies  in  the  attempt  to  bring  vividly  before 
him  the  great  importance  of  a  clear  knowledge  of  the  physical 
conceptions  involved  in  all  chemical  work,  and  the  necessity 
which  is  imposed  upon  him,  wherever  his  work  may  be  placed, 
of  making  these  conceptions  clear  to  his  pupils  as  necessity 
arises.  Without  this  the  work  in  chemistry  must  be  mechanical 
and  fruitless,  and  indeed,  although  dealing  with  the  sub- 


40  CHEMISTRY  IN  THE   CURRICULUM 

ject-matter  of  the  science,  it  cannot  justly  be  called  chemistry 
at  all. 

IV.     The  Time  to  be  allotted  to  Chemistry. 

The  subjects  which  have  long  been  established  in  the  cur- 
riculum in  most  cases  run  continuously  through  the  course,  and 
the  unit  of  work  is  seldom  less  than  a  year.  The  sciences, 
however,  in  the  struggle  for  recognition,  have  had  to  content 
themselves  with  a  bare  foothold,  and  in  a  majority  of  the 
secondary  schools  of  this  country  are  each  disposed  of  in 
brief  periods  of  twelve  weeks.  The  question  of  the  minimum 
length  of  time  which  may  be  assigned  to  chemistry,  consis- 
tently with  securing  the  best  value  for  the  efforts  of  teacher  and 
pupil,  is,  therefore,  one  of  the  greatest  importance. 

If  the  object  in  teaching  chemistry  were  simply  that  of  im- 
parting a  certain  amount  of  information  about  the  subject,  the 
A  Full  Year  result  would  be  considerable  in  proportion  to  the 
for  chemistry,  length  of  the  course,  no  matter  how  short  it  might 
be.  If,  however,  the  task  of  contributing  to  the  discipline  of 
the  pupil's  mind  is  to  be  assigned  to  it,  the  time  factor  requires 
careful  consideration.  If  we  take  into  account  the  fact  that, 
when  a  subject  is  taken  up  for  the  first  time,  familiarity  has  to 
be  acquired  with  a  new  material  of  study,  with  a  new  language 
and  mode  of  expression,  and,  in  the  case  of  a  science,  with  a 
new  mode  of  study  by  experiment  in  a  laboratory,  and  a  less 
familiar  form  of  exercise  for  the  reasoning  powers,  it  is  evident 
that  much  time  will  be  consumed  in  overcoming  the  initial 
difficulties.  In  the  case  of  chemistry  eight  or  ten  weeks  at 
least  must  pass  before  the  pupil  has  become  accustomed  to 
the  use  of  a  laboratory  and  has  reached  the  position  of  being 
able  to  study  the  new  subject  in  the  new  way.  The  effect  of 
experience,  which  is  always  cumulative,  is  most  markedly  so  in 
an  elementary  course  in  science,  and  even  after  twenty-four 
weeks'  work,  the  pupil  is  just  reaching  the  point  at  which  facility 
in  handling  the  subject  will  enable  him  to  make  really  rapid 
progress.  The  influential  committees  which  have  recently  re- 


CHEMISTRY  IN   THE  CURRICULUM  41 

ported  on  this  subject  have  been  unanimous  in  demanding  at 
least  a  year  for  chemistry  in  the  secondary  school. 

The  far  too  common  plan  of  teaching  three  sciences  in  a  year 
is  supported  by  the  argument  that  it  gives  more  variety,  but 
when  we  consider  that  each  of  the  sciences  introduces  a  new 
subject,  a  new  variety  of  material,  a  new  nomenclature,  new 
forms  of  manipulation,  and  to  some  extent  new  methods  of 
thought,  it  is  evident  that  the  repeated  change  from  one  sub- 
ject to  another  must  involve  a  great  expenditure  of  time  on 
the  mere  machinery  of  each  subject,  and  a  prodigious  loss  of 
power  in  throwing  away  at  each  transition  much  that  had  been 
acquired,  instead  of  using  it  as  the  foundation  for  still  greater 
and  more  rapid  advances  in  the  same  direction.  The  names 
of  all  the  sciences  may  be  included  in  the  curriculum,  but  it  is 
certain  that  if  their  number  reduces  too  greatly  the  time  allotted 
to  each,  the  sciences  themselves  will  never  get  within  reach  of 
the  pupil  excepting  in  name.  If  the  means  of  the  school  per- 
mit the  teaching  of  only  one  or  two  years  of  work  in  science, 
then  one  or  two  sciences  only  should  be  taught. 

The  Committee  of  Ten  recommends  that  at  least  two  hun- 
dred hours  be  devoted  to  chemistry,  and  that  one-half  of  this  time 
should  be  spent  in  the  laboratory.  The  Committee  on  College 
Entrance  Requirements  of  the  National  Education  Association, 
the  most  representative  educational  body  in  this  country,  rec- 
ommends that  at  least  four  periods  a  week  be  given  to  chem- 
istry, and  that  half  of  these  be  periods  of  double  length  spent  in 
the  laboratory.  They  add  that  a  longer  time  than  this  will 
be  required  if  chemistry  appears  before  the  third  year  of  the 
course.  The  Committee  of  Nine  of  the  New  York  State  Sci- 
ence Teachers'  Association,  in  its  report  published  by  the 
University  of  the  State  of  New  York  (High  School  Bulletin 
No.  7,  714),  recommends  an  even  longer  time.  If  the  period 
in  the  high  school  is  forty-five  minutes  in  length,  the  com- 
mittee demands  two  double  periods  weekly  in  the  laboratory, 
one  period  devoted  to  an  experimental  demonstration,  two 
periods  to  prepared  recitations,  and  suggests  that  three  ad- 


42  CHEMISTRY  IN    THE   CURRICULUM 

ditional   periods  will  be    required   for    text-book    and  library 
study. 

The  difficulty  of  securing  consecutive  periods  for  laboratory 
work  seems  to  be  so  great  that  particular  emphasis  should  be 
placed  on  the  importance  of  this.  When  the  periods  are  short, 
experiments  requiring  construction  of  apparatus,  and  occupying 
more  than  a  very  few  minutes  of  time  in  their  performance,  can 
only  be  accomplished  under  considerable  difficulties.  If  it  is 
found  impossible  to  secure  double  periods,  the  apparatus  may 
be  prepared  in  advance  by  the  teacher,  and  thus  the  exclu- 
sion of  some  experiments  of  fundamental  importance  may  be 
avoided. 

V.     Continuous  Courses  in  Chemistry. 
REFERENCES. 

Wilson,  C.  C.  The  Place  of  Science  in  the  Preparatory  Schools. 
SCHOOL  REVIEW,  VI.  (1898),  211-214. 

Palmer,  C.  S.  Specialization  in  Preparatory  Natural  Science,  ibid., 
659-671. 

Although  the  extension  of  the  courses  in  chemistry  in  secon- 
dary schools  to  the  length  of  one  year  has  not  yet  been  accom- 
Arguments  plished  in  the  majority  of  the  high  schools  of  the 
in  Favour  of  country,  a  movement  in  favour  of  the  establishment 
lon>  of  three  and  four  year  courses  in  this  subject  has 
acquired  such  prominence  that  reference  to  it  cannot  be 
omitted.  In  recent  articles  the  arguments  in  favour  of  this 
extension  have  been  marshalled  with  such  earnestness,  and  it 
must  be  admitted  with  some  degree  of  plausibility.  The  dis- 
ciplinary value  of  the  old  curriculum  depended  upon  the  con- 
tinuous courses  in  Latin,  Greek,  and  mathematics  which  it 
contained.  The  disciplinary  value  of  a  similar  course  in  chem- 
istry, or  one  of  the  other  sciences,  properly  taught,  although 
we  have  no  experience  of  it  in  the  secondary  school  period, 
would  undoubtedly  be  not  less  than  that  of  the  older  subjects. 
Differing  in  kind  from  these,  as  they  differ  from  one  another, 


CHEMISTRY  IN  THE   CURRICULUM  43 

it  would  be  a  valuable  addition  to  the  training  of  the  pupil. 
It  would  also  give  a  wider  selection  of  continuous  studies,  and 
enable  those  who  are  unable  to  secure  the  greatest  benefit 
from  the  classical  course  to  get  a  more  congenial,  and,  at  the 
same  time,  a  really  worthy  substitute  for  Greek. 

The  counter-argument  that  the  study  of  science  has  a  nar- 
rowing influence  may  be  branded  at  once  as  preposterous.  Any 
study,  even  Latin,  may  have  a  narrowing  influence  TwoYears 
if  taught  by  a  narrow  man  in  a  narrow  way.  But  the  Maximum 
this  suggests  one  real  difficulty,  namely,  that  no  non- 
technical or  liberal  course  for  the  second  or  third  years  of  chem- 
istry has  yet  been  worked  but.1  The  real  obstacle,  however,  in 
the  case  of  chemistry,  and  we  are  not  concerned  with  the  ques- 
tion as  it  affects  other  sciences,  is  that  if  we  agree  that  it  should 
be  preceded  by  physics,  which  in  turn  is  preceded  by  algebra, 
at  least  two  years,  and  more  often  three  years  of  the  high  school 
course  will  have  passed  before  the  pupil  is  ready  to  begin  the 
subject.  Even  taking  the  possible  redistribution  of  the  work  of 
physics  and  chemistry  into  account,  it  does  not  seem  likely  that 
more  than  two  years  of  chemistry  can  in  any  case  be  secured. 
In  a  few  high  schools  this  amount  of  instruction  is  given,  and  given 
successfully.  The  question,  however,  of  outlining  the  work  of  the 
second  year  cannot  become  pressing  as  long  as  the  preparation 
of  a  majority  of  teachers  is  not  sufficient  for  a  single  year. 

In  spite  of  the  obvious  and  weighty  difficulties  in  the  way  of 
this  so-called  "  specialization  "  in  school  science,  it  is  surprising 
how  rapidly  sentiment  in  favour  of  it  seems  to  be  de-  some  Favour 
veloping.  Mr.  Wilson  mentions  ascertaining  the  aWe  Opinions, 
opinions  of  about  two  hundred  teachers,  of  whom  only  one-third 
were  college  professors,  on  the  question  whether  they  preferred 
(a)  to  divide  the  time  among  four  branches  of  science,  or  (b)  to 
give  the  pupil  a  choice  of  four  sciences  or  two  years'  work  each 
in  any  two  of  the  four  sciences,  or  (c)  to  devote  four  years  to 
continuous  study  on  one  subject.  Only  forty-three  per  cent 

1  This  subject  is  discussed  further  in  connection  with  that  of  the  train- 
ing of  the  teacher  (chapter  VIII). 


44  CHEMISTRY  IN   THE   CURRICULUM 

favoured  the  first  plan,  and  many  of  these  may  have  done  so 
simply  because  they  disliked  the  other  two  still  more,  while  forty- 
two  per  cent  favoured  the  second,  and  fifteen  per  cent  favoured 
the  third.  Of  those  preferring  the  last  plan,  eight  or  more  were 
teachers  in  secondary  schools. 

VI.     Articulation  of  School  and  College  Chemistry. 
REFERENCES. 

Palmer,  C.  S.  Resume  and  Critique  of  the  Tabulated  College  Require- 
ments in  Natural  Sciences.  SCHOOL  REVIEW,  IV.  (June,  1896),  452-460. 

Smith,  Alexander.  Articulation  of  School  and  College  Work  in  the 
Sciences.  SCHOOL  REVIEW,  VII.  (1899),  411,  453,  527. 

While  it  is  generally  admitted  that  the  work  of  the  school 
should  be  arranged  exclusively  with  reference  to  the  needs  of 
the  pupils  of  the  school  itself,  and  without  reference  to  any 
special  section  of  them  which  may  harbour  the  intention  of  after- 
wards proceeding  to  college,  there  is  no  question  but  that  the 
college  has  exercised  a  definite  if  subordinate  influence  on  the 
evolution  of  the  school  course.  In  some  subjects,  the  college 
has  assisted  in  setting  the  pace  and  marking  out  the  path  which 
has  finally  been  adopted  as  best  for  the  pupil,  whether  he  goes  to 
college  afterwards  or  not.  Except  in  a  few  isolated  instances, 
the  correlation  between  the  work  of  the  two  institutions  unfort- 
unately has  been  confined  to  languages  and  mathematics.  In 
these  subjects  it  is  possible  for  the  pupils  who  go  "to  college  to 
continue  without  interruption  or  loss  of  ground  the  studies 
which  they  pursued  in  school.  The  achievement  of  a  similar 
articulation  in  the  sciences  has  encountered  so  many  difficulties 
that  it  has  as  yet  made  practically  no  progress. 

The  first  difficulty  lies  in  the  extraordinary  diversity  in  length 
and  in  content  of  the  courses  in  the  same  science  in  different 
School  Chem-  sch°°ls'  In  chemistry,  the  time  varies  from  twelve 
istry  a  Vari-  to  forty  weeks,  and  the  instruction  may  be  entirely 
able  Quantity.  .  ,  ,  •  i  •  ,  •  ,-  • 

in  general  chemistry,  almost  entirely  m  qualitative 

analysis,  or  it  may  dispense  with  the  laboratory.     The  college, 


CHEMISTRY  IN   THE   CURRICULUM  45 

drawing  its  freshmen  from  a  hundred  different  schools,  cannot 
furnish  a  course  which  will  fit  equally  so  many  differing  founda- 
tions, and  it  does  not  attempt  the  task.  President  Eliot  says, 
"  It  would  be  a  pity  if  we  could  not  adapt  our  courses  in  college 
to  any  good  teaching  in  the  schools."  If  Latin  and  mathematics, 
however,  had  remained  one-tenth  part  as  full  of  divergencies  as 
school  chemistry,  the  present  system  of  co-operation  would 
never  have  been  brought  about.  It  is  difficult  to  believe  that 
chemistry  possesses  any  property  which  makes  this  divergence 
unavoidable. 

The  second  difficulty  in  the  way  of  articulation  is  the  con- 
siderable diversity  in  the  elementary  courses  of  different  colleges, 
and  therefore  in  the  work,  part  or  all  of  which,  pupils  Attitude  of 
in  the  same  school  in  going  to  these  different  col-  tte  Colleses- 
leges  must  attempt  to  anticipate.      A  third  difficulty  is  that 
many  colleges  give  no  admission  credit  for  chemistry,1  and  the 


1  The  preliminary  report  of  the  Committee  on  College  Entrance 
Requirements  of  the  National  Education  Association,  published  in 
the  SCHOOL  REVIEW,  IV.  (June,  1896),  341-412,  gives  some  startling 
information  in  regard  to  this  subject.  Of  the  fifty-six  colleges  and  uni- 
versities whose  admission  requirements  were  discussed,  only  thirty  accept 
chemistry  at  all.  A  further  study  of  the  relation  between  admission  and 
college  chemistry  in  these  thirty  institutions,  which  I  had  occasion  to 
make  and  have  fully  discussed  in  the  SCHOOL  REVIEW,  VII.  (1889), 
411,  53,  527,  shows  that  only  three  have  definite  entrance  requirements, 
and  provide  a  definite  mode  of  handling  those  who  offer  them.  A  dozen 
or  so  place  the  students  who  offer  chemistry  into  the  college  course  along 
with  beginners,  and  the  remainder  seem  to  attempt  a  rough  sifting  by 
which  the  better  prepared  students  go  into  advanced  work,  and  the  less 
well  prepared  into  the  elementary  course. 

Professor  Bardwell  of  the  Massachusetts  Institute  of  Technology 
presented  to  the  Sixth  Meeting  of  the  New  England  Association  of  chem- 
istry teachers  some  facts  which  illustrate  the  method  in  the  last  class  of 
institutions.  In  the  autumn  of  1899,  one  hundred  and  fifty-eight  students 
offered  chemistry  for  admission  to  the  Institute,  being  50.3  per  cent  of 
the  total  number  entering.  After  five  weeks  eighty-six  of  these  students 
remained  in  advanced  courses,  while  seventy-two  retired  voluntarily  into 
the  elementary  course.  It  is  evident  that  a  majority  of  the  eighty-six 
were  most  likely  only  partially  fitted  for  the  work  in  which  they  found 
themselves,  while  the  seventy-two  were  all  misfits  in  the  elementary  course, 
since  they  had  all  studied  more  or  less  of  it  before.  It  is  evident  from 


46  CHEMISTRY  IN   THE   CURRICULUM 

rest,  with  few  exceptions,  give  credit  for  anything  that  is 
presented,  and  thus  make  the  arrangement  of  a  logical  sequel 
to  high  school  work  in  the  subject  within  their  own  walls 
impossible. 

The  few  universities  which  insist  upon  a  definite  amount  and 
kind  of  chemistry  do  not  agree  at  all  in  regard  to  the  kind,  and 
thus  when  the  school  seeks  the  advice  of  the  college,  as  it  often 
does,  the  utterances  of  the  latter  in  regard  to  chemistry  lead  to 
nothing  but  discouragement  and  distraction.  The  Committee 
of  Ten  reported  definitely  "  that  there  should  be  no  difference 
in  the  treatment  of  physics,  chemistry,  and  astronomy  for  those 
going  to  college  and  scientific  school  and  those  going  to  neither." 
The  principle  would  have  been  something  more  than  a  mere 
doctrinaire  statement  if  it  had  read,  "When  the  secondary 
schools  have  decided  upon  the  length,  aim  and  content  of  their 
course  in  chemistry,  all  colleges  should  accept  this  for  admis- 
sion." 1 

The  fourth  difficulty  in  the  way  of  articulation  is  that  no 
advancement  is  granted  to  pupils  who  offer  chemistry  as  an  ad- 
mission subject.  I  have  elsewhere  discussed  this  subject  more 
fully,  and  may  be  permitted  to  quote  a  few  lines.2 

"  The  college  should  grant  advancement  in  the  series  of  its 
courses  in  each  science  to  an  extent  corresponding  to  the  ad- 
mission credit  given.  In  other  words,  it  must  recognise  ade- 
quately, and  in  a  practical  form,  the  extent  to  which  the  school 
work  may  fairly  claim  to  constitute  an  anticipation  of  its  own. 

"  To  effect  this,  each  department  in  the  college  must  adapt 
its  own  courses  so  that  one  of  them  shall  offer  a  suitable  contin- 
uation of  the  preparatory  work.  This  will  be  open  to  those 


this  that  the  Institute  has  no  definite  requirement  in  admission  chemistry, 
and  must,  like  other  institutions  of  the  same  class,  share  with  the  schools 
the  blame  for  this  chaotic  state  of  affairs. 

1  Arguments  similar  to  the  above,  and  leading  to  the  same  conclusions, 
have  been  urged  most  strongly  by  the    Committee  of  Nine  of  the  New 
York  State  Science  Teachers'  Association  in  its  first  report  (University 
of  the  State  of  New  York,  High  School  Bulletin  No.  2,  478-480). 

2  From  the  SCHOOL  REVIEW,  VII.  456. 


CHEMISTRY  IN  THE   CURRICULUM  47 

students  who  enter  with  a  credit  in  the  subject,  and  such  stu- 
dents should  never  be  required  to  begin  the  science  over  again 
in  the  same  class  with  those  who  lack  this  credit  and 
preparation." 

The  course  in  continuation  of  school  work  will  not  usually  be 
the  second  regular  college  course,  for  the  school  work  will  not 
be  the  equivalent  of  the  first  course  in  college. 

Thip  Pollpp'f1 

When  the  college,  as  it  often  does,  attempts  nothing  must  offer 

beyond  a  secondary  school  course  in  elementary   Two  indepen- 
J  .      }     dent  Courses. 

chemistry,  it  deliberately  throws  away  the  advan- 
tages which  the  more  rigid  selection  of  its  students,  the  smaller 
size  of  the  classes,  the  greater  maturity  of  the  constituents  of 
these  classes,  and  the  greater  amount  of  work  which  can  conse- 
quently be  demanded  of  them,  place  in  its  hands.  The  college 
introductory  course  should  be  heavier  by  at  least  a  half,  and  a 
distinct  class  should  be  formed  for  those  who  are  not  beginners 
and  desire  a  sequel  to  secondary  school  chemistry.  This  ar- 
rangement should  certainly  be  possible  in  the  larger  universities, 
and  especially  in  technical  and  medical  institutions  in  which  all 
the  students  are  required  to  study  chemistry,  and  in  which, 
therefore,  a  sufficiently  large  number  will  have  offered  it  for 
admission  to  warrant  the  formation  of  a  separate  class.  Where 
no  proper  sequel  is  offered,  and  chemistry  inside  the  college  is 
optional,  the  pupil  takes  an  elementary  course,  in  which  much 
that  he  has  already  studied  is  repeated,  of  his  own  free  will. 
Where  the  pupil  is  required  to  take  college  chemistry,  however, 
and  admission  credit  has  been  granted,  the  institution  is  under 
an  obligation  to  furnish  fit  instruction  to  the  candidates. 

The  movement  in  favour  of  unity  in  the  matter  of  secondary 
school  chemistry  will  doubtless  be  materially  assisted  by  the 
recent  inauguration  of  a  college  entrance  examination  board,  by 
the  Association  of  Colleges  and  Schools  of  the  Middle  States  and 
Maryland,  and  the  preparation  by  it  of  syllabuses  l  of  admission 


1  The  requirements  in  all  subjects  may  be  obtained  by  transmitting 
the  price,  ten  cents,  to  the  Secretary  of  the  College  Entrance  Examina- 
tion Board,  Sub-station  84,  New  York,  N.  Y. 


48  CHEMISTRY  IN   THE   CURRICULUM 

work  in  all  secondary  school  subjects.  The  syllabus  in  chem- 
istry is  based  upon  the  report  of  the  Committee  of  the  National 
Educational  Association,  and  will  probably  be  accepted  not  only 
by  the  universities  within  the  association,  but  also  by  the  great 
majority  of  the  institutions  of  learning  in  the  country. 


CHAPTER  III 

THE   INTRODUCTION   OF   THE   SUBJECT 
BIBLIOGRAPHY. 

Richards,  T.  W.  Requirements  in  Chemistry  for  Entrance  to  Harvard 
College.  Cambridge,  published  by  the  University  (1900).  Pp.  4-10. 

Freer,  P.  C.  The  Teaching  of  Beginning  Chemistry.  Proceedings  of 
the  National  Educational  Association,  1896.  Reprinted  in  SCIENCE 
[N.  8.],  IV.  130-135. 

Smith,  Alexander.  The  Value  of  Chemistry.  Proceedings  of  the 
National  Educational  Association,  1897.  Pp.  945-951. 

Report  of  the  Committee  of  Nine  of  the  New  York  State  Science 
Teachers'  Association.  High  School  Bulletin  No.  7.  Albany,  N.  Y., 
The  University  of  the  State  of  New  York,  1900.  Pp.  708-721. 

I.     Impediments  to  be  overcome  or  avoided. 

WHILE  the  introduction  of  any  new  subject  must  of  necessity 
be  difficult,  there  are  special  reasons  which  make  the  demand 
for  unusual  tact  and  skill  on  the  part  of  the  teacher 
of  science  imperative.     The  introduction  of  a  new  Lanuae 


language,  for  example,  does  not  present  the  same  and  Science 
degree  and  kind  of  difficulty.  The  pupil  has  been 
accustomed  from  his  infancy  to  handling  the  problem  of  words, 
their  meaning,  and  their  relations,  and  there  is  no  novelty  in 
the  material,  or,  to  any  great  extent,  in  the  method.  The 
operation  of  noting  the  usage  of  words,  for  example,  and 
determining  their  precise  significance,  "  the  formation  of  hy- 
potheses .  .  .  and  repeated  modification  of  hypotheses  after 
they  have  been  brought  to  the  touchstone  of  experience," 
and,  in  general,  the  operation  of  organizing  isolated  facts  into 
knowledge,  which  Professor  J.  G.  Macgregor  has  styled  knowl- 
edge-making, has,  in  the  direction  of  language,  become  a  habit. 
Much  of  this  work  may  have  been  unconscious,  but  it  has  none 

4 


50        THE  INTRODUCTION  OF  THE  SUBJECT 

the  less  resulted  in  education  with  especial  application  to  a  par- 
ticular kind  of  problem.  The  objects  of  the  material  world  have 
not  been  studied  with  anything  like  the  same  care,  for  attention 
to  physical  matters  has  not  occupied  almost  every  waking  instant, 
and  there  has  not  been  the  same  inexorable  necessity  for  mi- 
nute and  exhaustive  organization  of  the  phenomena  which  they 
present. 

Then,  too,  the  study  of  language  furnishes  an  endless  suc- 
cession of  simple  problems  in  which  the  same  forms  recur  at 
Science  more  short  intervals  an  endless  number  of  times.  A 
Difficult.  science,  on  the  other  hand,  presents  "  problems 
with  a  greater  range  of  difficulty  on  a  material  which  is  in 
general  more  complex." 

Furthermore,  when  a  new  language  is  presented,  the  assist- 
ance which  the  pupil  receives  from  the  grammar  and  diction- 
ary has  no  parallel  in  scientific  work.  The  contents  of  these 
aids  to  study  are  classified  in  such  a  way  that  the  problem  of 
ascertaining  the  meaning  of  a  word  or  phrase  can  be  at  once 
reduced  within  certain  narrow,  clearly  defined  limits.  The 
laboratory  directions,  indeed,  attempt  to  instruct  the  pupil  how 
he  shall  himself  produce  that  which  in  science  takes  the  place 
of  the  text,  the  phenomenon  to  be  studied.  But  unless  these 
directions  play  the  part  of  an  interlinear  translation  also,  he  has 
to  provide  from  his  own  previous  experience  the  ability  to  sepa- 
rate the  significant  from  the  insignificant  factors  among  the 
many  details  he  may  observe,  and  to  furnish,  upon  the  same 
presumably  rather  meagre  basis,  the  correct  interpretation. 
The  teacher  always  has  it  in  his  power  to  simplify  the  problem 
by  affording  guidance,  but,  if  this  is  carried  too  far,  the  benefit 
of  learning  from  experience  under  conditions  which  far  more 
closely  resemble  those  of  actual  life  than  is  the  case  in  language 
study,  is  snatched  from  the  pupil's  grasp.  Acquiring  the  ability 
to  make  knowledge  is  education,  and  to  shield  the  pupil  from 
the  necessity  of  doing  this  with  the  material  which  science  sup- 
plies, is  to  deprive  him  of  that  element  in  his  training  which 
science  is  in  an  especial  degree  fitted  to  furnish. 


THE  INTRODUCTION  OF  THE  SUBJECT       5  I 

Not  only,  however,  does  the  beginning  work  in  a  science 
present  an  unfamiliar  material  for  study,  but  it  should  seek  to 
cultivate  an   attitude   which   is  for   the  most  part  j^^^ 
entirely  new.  f  The  work  in  chemistry  can  be  made  Spirit  in 

4*  Cpjprtpp 

almost  wholly  inductive  in  method,  and  must  be  k 
made  altogether  so  in  spiriy  The  pupil  encounters  an  addi- 
tional difficulty  in  the  acquired  mental  habit  which  he  has  of 
developing  consequences  by  speculation.  It  is  the  hardest 
thing  in  the  world  to  compel  him  to  stick  closely  to  the  facts 
and  to  test  such  inferences  as  he  may  draw  by  renewed  scrutiny 
of  the  data,  and  perhaps  the  performance  of  new  experiments, 
before  adopting  them.  The  symmetry  of  an  idea,  and  its  logi- 
cal harmony  with  conceptions  already  existing  in  his  mind,  blind 
him  to  the  fact  that  a  dozen  competing  ideas  might  have  arisen 
in  the  same  connection,  and  yet  none  of  them  be  confirmed  by 
experience.  In  geometry  he  is  accustomed  to  the  developing 
of  a  system  from  a  few  simple  conceptions,  and  he  has  still  to 
lea\that  in  science  a  multitude  of  facts  are  required  for  the 
foundation  of  one  conception.  Not  only  does  the  pupil  suffer 
from  wft  difficulty,  but  the  teacher  himself  may  follow  the  lines 
of  least  resistance,  and,  allured  by  the  rapid  progress  the  pupils 
make,  conform  his  teaching  to  methods  to  which  they  are  ac- 
customed, and  so  throw  away  the  opportunity  of  making  a  new 
start  which  the  study  of  a  science  furnishes.  He  may  thus  all 
too  easily  pervert  it  into  a  continuation  of  the  same  kind  of  dis- 
cipline, instead  of  making  it  the  starting  point  of  a  new  one. 
The  teacher  must  be  continually  on  the  watch  lest  defects  in 
his  own  training,  which  he  has  not  later  observed  and  remedied, 
lead  him  to  teach  chemistry  as  a  dogmatic  system  of  principles 
with  which  the  concrete  experience  in  the  laboratory  has  little 
more  than  a  nodding  acquaintance. 

Still  another  feature  of  chemical  work  which  in  some  ways 
forms  an  impediment  to  the  beginner,  is  the  attitude  of  an 
original  observer  in  which  he  is  to  be  placed.  This  attitude  is 
a  strange  one  to  him,  for  he  has  been  accustomed  to  accept 
facts  from  books  or  his  teacher  as  the  basis  of  his  work,  and 


52         THE  INTRODUCTION  OF  THE  SUBJECT 

even  to  derive  most  of  his  opinions  from  sources  other  than 
his  own  intelligence.  It  is  difficult  if  not  impossible  to  con- 
Self-reliance  ^uct  ^ie  elementary  instruction  in  a  language  in  a 
in  the  Lab-  way  which  will  have  any  other  effect  than  to  confirm 
oratory.  ^e  m}nd  of  ^Q  ^^  m  thjg  attjtu(je.  Before  be- 
ginning a  science,  therefore,  he  has  acquired  the  habit  of  rely- 
ing upon  authority  for  most  of  what  he  learns.  I  It  is  the  special 
boast  of  work  in  a  science,  that,  as  it  proceeds,  the  pupil  is 
bound  to  see  that  the  facts  may  be  derived  from  his  own  obser- 
vation, and  the  conclusions  may  be  drawn  by  his  own  unaided 
efforts.  It  is  held  that  scientific  work  thus  furnishes  an  exer- 
cise in  indejDendent  thought  much  more  readily  than  the  study 
of  language.  \ 

The  number  and  subtlety  of  these  pitfalls  to  which  the  intro- 
ductory work  in  chemistry  is  especially  liable,  make  it  impor- 
tant that  we  should  devote  a  chapter  to  the  discussion  of  the 
most  natural  method  of  approaching  the  subject,  and  of  the 
principles  which  should  first  be  the  objective  of  the  instruction. 


II.    What  Phenomena  shall  furnish  the  Basis  of  the  Introduc- 
tory Work. 

The  course  in  chemistry  frequently  begins  with  a  part  which 
is  intended  to  be  introductory,  and  is  not  a  portion  of  the  sys- 
tematic presentation  of  the  subject.  There  must  of  necessity 
be  some  attempt  during  the  earlier  part  of  the  course  to  mar- 
shal before  the  pupil  the  various  types  of  chemical  change,  the 
most  characteristic  features  of  chemical  action,  and  the  constantly 
necessary  habits  which  he  should  form  in  doing  chemical  work. 
In  this  chapter  we  shall  not  attempt  to  elaborate  any  novel 
method  of  approach.  We  shall  simply  seek  to  decide  which 
are  the  most  important  generalizations,  and  how  they  may  be 
brought  to  the  knowledge  of  the  pupil.  In  concrete  form  our 
conclusions  will  be  found  embodied  in  many  of  the  available 
text-books.  The  common  statement  of  the  nature  of  the 
subject-matter  of  the  science,  which  is  usually  to  the  effect 


THE  INTRODUCTION  OF  THE  SUBJECT      53 

that  chemistry  deals  with  the  changes  in  composition  which 
matter  undergoes,  and  with  the  accompanying  physical  phe- 
nomena, will  furnish  us  with  a  starting  point. 

a.  Classification  of  Various  Principles  of  Arrangement :  — The 
elementary  study  should  clearly  begin  with  familiar  forms  of 
matter,  and  familiar  phenomena  should  be  selected.  T^  Earliest 
If  any  of  the  earlier  facts  are  unfamiliar,  they  must  Observations, 
at  least  be  closely  related  to  those  which  are  familiar.  Then, 
also,  the  selection  must  consider  the  facility  with  which  the  phe- 
nomena can  be  subjected  to  experimental  study  by  one  who  is 
as  yet  untrained  in  the  methods  of  the  science.  Thus  while  the 
action  of  soap  upon  water,  and  the  effects  of  the  caustic  soda 
produced  by  it  upon  the  skin,  are  exceedingly  familiar,  they  are 
not  capable  of  simple  experimental  investigation.  Finally,  the 
chemical  changes  studied  must  be  of  a  simple  nature  in  the 
chemical  point  of  view,  since  then  alone  will  they  form  an  easy 
vehicle  for  the  passage  from  the  realm  of  simple  fact  to  that  of 
chemical  knowledge. 

At  this  point  a  divergence  takes  place  which  enables  us  to 
classify  the  ways  of  treating  the  subject  roughly  into  three  kinds, 
and,  it  may  be  remarked,  imposes  upon  us  ulti- 

Xfl6  Tnrcc 

mately  the  necessity  of  deciding  which  is  more  Principles  of 
applicable  to  the  case  of  any  given  set  of  pupils.  Arrangement. 
It  will  be  noted  that  we  are  speaking  at  present  mainly  of  the 
ways  of  selecting  the  content,  and  not  of  modes  of  presenta- 
tion, inductive,  deductive,  or  otherwise.  One  method  proceeds 
by  selecting  from  common  materials  those  whose  general  physi- 
cal properties  must  be  familiar  even  to  the  youngest,  namely, 
solids,  and  frequently  devotes  a  very  considerable  amount  of 
attention  to  quite  a  series  of  studies  from  which  work  with  gases 
is,  as  far  as  possible,  excluded.  Another  variety  of  treatment 
deals  indeed  with  familiar  substances  to  begin  with,  but  does 
not  restrict  itself  to  the  most  familiar  materials  physically.  In 
fact,  it  deliberately  leads  up  as  rapidly  as  possible  to  the  prop- 
erties of  air  and  the  chemical  effects  of  oxygen,  pursuing  its 
way  after  that  largely  through  the  study  of  other  gases. 


54        THE  INTRODUCTION  OF  THE  SUBJECT 

When  the  former  of  these  methods  is  employed,  the  main 
object  is  to  put  the  pupil  in  the  attitude  of  a  discoverer.  The 
Nature  study  problems  are  selected  therefore,  not  because  of 
Method.  their  chemical  importance  or  their  relation  to  the 

development  of  an  organized  knowledge  of  the  science,  but 
solely  because  they  are  simple,  since  thus  alone  is  there  any 
hope  of  realizing  the  object  in  view  with  any  degree  of  com- 
pleteness. The  facts  as  they  are  accumulated  lend  themselves 
easily  in  this  less  systematic  study  of  the  subject  to  the  con- 
struction of  the  ordinary  generalizations  of  the  science.  But 
the  ultimate  results  come  more  slowly  than  they  would  with  the 
more  systematic  treatment. 

Largely  different  must  be  the  arrangement  of  the  work,  if  the 
most  logical  presentation  of  the  framework  of  the  science  is 
Theoretical  to  ^e  rna(^e  one  °f  tne  objects.  While  the  same 
Method.  methods  are  pursued  in  matters  of  detail,  this  plan 

seeks,  as  directly  as  possible,  to  reach  the  means  of  explaining 
the  basis  of  our  modern  mode  of  expressing  the  quantitative 
relations  involved  in  chemical  change.  In  other  words,  this 
plan  handles  the  gases  as  soon  as  possible  -in  order  that  it  may 
quickly  lead  up  to  the  explanation  of  Avogadro's  hypothesis 
and  the  consequences  which  follow  from  it.  Until  this  hy- 
pothesis has  been  discussed,  everything  else  relating  to  the 
appropriate  statement  of  quantitative  relations  must  remain 
largely  in  suspense,  unless  we  are  willing  to  teach  these  matters 
in  an  empirical  manner  without  examining  their  basis  or  know- 
ing the  centre  from  which  they  are  controlled.  When  the 
attempt  is  made  boldly  thus  to  grapple  with  the  foundations 
of  chemistry,  the  pupil  must  perforce  be  brought  rapidly  through 
the  most  indispensable  stages  leading  to  the  study  of  chemical 
change  in  the  light  of  Avogadro's  hypothesis.  His  early  work 
must  thus  deal  largely  with  gaseous  materials,  and  the  peda- 
gogical advantage  of  greater  familiarity  which  solid  bodies  afford 
must  be  sacrificed. 

Still  a  third  method,  which,  however,  is  closely  related  to  the 
last,  may  be  defined.  In  this  arrangement  of  the  material  the 


THE  INTRODUCTION  OF  THE  SUBJECT       55 

desire  is,  as  rapidly  as  possible,  to  bend  the  order  of  study  into 
a  series  of  chapters  dealing  with  successive  elements,  arranged 
in  an  order  something  like  that  which,  in  spite  of  The  -g^^fa^ 
slight  variations,  is  in  its  general  features  com-  Systematic 
mon  to  most  books.  The  second  method  was 
an  arrangement  with  reference  to  theory ;  the  third  is  an 
arrangement  with  reference  to  chemical  materials,  with  the 
theory  distributed  at  convenient  intervals.  The  order  here 
seems  to  be  determined  in  the  first  place  by  a  desire  to  con- 
form to  the  historical  development  of  the  subject.  Oxygen, 
air,  and  water  thus  find  an  early  place.  This  motif  presently 
gives  place  to  the  impulse  to  arrange  the  elements  in  accord- 
ance with  the  natural  families. 

Each  of  these  methods  of  arrangement,  the  nature  study,  the 
theoretical,  and  the  historico-systematic,  has  its  merits.  The 
decision  as  to  which  is  more  suitable  will  depend  largely  upon 
the  advancement  of  the  pupil  whose  instruction  is  under  con- 
sideration. The  first  method  is  practically  that  which  is  adopted 
in  nature  study,  excepting  that  it  may  be  expanded  beyond  the 
limits  of  the  familiar  materials  to  which  the  latter  is  confined. 
It  is  applicable  to  the  youngest  scholars,  and  in  general  would 
probably  be  the  best  arrangement  for  pupils  in  the  first  year  of 
the  secondary  school.  The  two  latter  methods,  suitably  modi- 
fied by  importations  from  the  former,  might  enter  largely  into  a 
course  given  in  the  later  years  of  the  secondary  school,  espe- 
cially if  the  pupils  had  already  studied  physics.  Their  greater 
maturity,  as  the  result  of  continuous  work  in  languages,  mathe- 
matics, and  physics,  would  more  than  offset  the  more  rapid 
progress  they  would  be  called  upon  to  make  through  unfamiliar 
ground.  The  more  highly  developed  intelligence  required  for 
the  successful  accomplishment  of  the  more  difficult  task  should 
be  by  this  time  available. 

b.  Various  Arrangements  Illustrated  by  Reference  to  Existing 
Text-books :  —  It  is  so  important  that  the  teacher  should  have  a 
clear  idea  of  what  is  implied  in  the  arrangement  of  the  text -book 
which  he  may  adopt,  and  of  the  precise  demands  which  this 


56        THE  INTRODUCTION  OF  THE  SUBJECT 

will  make  upon  his  pupils,  that  it  may  be  well  to  indicate  books 
which  will  furnish  examples  of  each  of  these  methods  of  han- 
dling the  subject. 

The  best  example  which  I  know  of  a  work  of  the  first  kind 
is  An  Introduction  to  the  Study  of  Chemistry  by  Professor  Perkin 
The  Nature  °^  Owens  College  and  Dr.  Lean  l  of  The  Friends' 
study  Method.  School,  Ackworth.  The  study  of  chemical  change 
begins  (p.  126)  with  an  experimental  examination  of  common 
salt,  chalk,  sand,  washing  soda,  iron  pyrites,  and  other  common 
materials.  This  is  followed  by  a  study  of  the  common  acids, 
and  common  alkalies,  and  this  again  by  the  relation  between 
acids,  bases,  and  salts.  The  next  topic  is  the  '  fixed  air '  of 
Black,  followed  by  rusting  and  combustion.  The  remaining 
subjects,  which  are  not  numerous,  need  not  be  given.  There  is 
no  attempt  to  develop  the  science  in  a  conventional  manner. 
The  way  in  which  ordinary  knowledge  of  familiar  materials  is 
gradually  transformed  into  scientific  knowledge  of  the  same 
things  is  worthy  of  careful  examination. 

Aside  from  this,  which  is  our  main  reason  for  mentioning 
the  book,  it  presents  other  features  which  make  it  exceedingly 
instructive.  The  first  part  (up  to  p.  125)  deals  entirely  with 
physical  properties.  This  is  doubtless  done  in  recognition 
of  the  fact  that  the  pupils  using  it  will  be  entirely  ignorant  of 
physics.  The  selection  of  material,  however,  is  naturally  not  that 
which  the  physicist  would  make  in  presenting  his  subject  sym- 
metrically, but  shows  rather  the  parts  of  physics  particularly 
important  in  chemical  observation.  We  shall  revert  to  this  sub- 
ject presently.  The  reader  accustomed  to  the  decoration  of 
the  pages  of  every  chemical  work  with  numerous  equations,  and 
supposing  that  these  are  indispensable  parts  of  the  science,  will 
be  surprised  to  find  that  in  a  course  of  this  kind  they  may  be 
dispensed  with  entirely  without  appreciable  loss  in  clearness. 
Then,  too,  since  the  work  does  not  pretend  to  be  a  treatise  on 
chemistry,  it  gains  the  unquestioned  right  to  omit  what  it 

1  Perkin  and  Lean.  An  Introduction  to  the  Study  of  Chemistry.  Lon- 
don and  New  York,  Macmillan.  1896. 


THE  INTRODUCTION  OF  THE  SUBJECT      $? 

pleases,  and  thus  shows  that  much  chemistry  of  a  perfectly 
sound  description  may  be  taught  without  a  single  mention  of 
atoms,  molecules,  or  valency.  While  the  presence  of  these  is 
doubtless  demanded  in  a  book  treating  the  subject  by  the 
second  or  third  method,  a  study  of  the  aspect  which  chemistry 
presents  in  their  absence  will  prove  exceedingly  instructive  to 
any  who  may  think  that  chemistry  begins  with  these  concep- 
tions, and  it  is  to  be  feared  sometimes  act  as  if  it  ended  there 
also. 

Much  of  the  recent  discussion  of  the  teaching  of  chemistry 
in  Great  Britain  has  been  concerned  with  urging  the  moulding 
of  instruction  in  the  subject  on  the  lines  of  that  Method  used  in 
method  of  the  three  which  we  are  now  discussing.  Great  Britain. 
A  syllabus  of  elementary  chemistry  published  by  the  Board  of 
Education,1  described  as  the  'alternative  elementary  stage,' 
furnishes  another  instructive  example  of  what  we  have  called 
the  nature  study  method. 

A  Committee  of  the  British  Association2  suggested  a  plan 
of  study  closely  resembling  those  we  have  just  mentioned.  The 
new  Syllabuses8  issued  by  the  Incorporated  Association  of 
Head  Masters  also  present  a  well-devised  and  thoroughly  tested 
course  of  a  similar  kind. 

As  we  have  suggested,  the  plans  of  the  first  kind  are   not 
accepted  as  the  basis  of  such  work  as  is  usually  attempted  in  the 
later  years   of  the   secondary  school  in  America. 
They  do  not  present  that  connected  and  complete  American 
account  of  the  subject  which  in  these  years  is  gen-   |econdary 
erally  demanded.     Pupils  trained  with  their  assist- 
ance would  have  a  sound  knowledge  of  chemistry,  so  far  as  that 
subject  had  been  covered,  but  they  would  not  be  able  to  pass 

1  Directory,  with   Regulations  for  Science  and  Art  Classes.     London, 
issued  annually  by  the  Board  of  Education  and  sold  by  Eyre  &  Spot- 
tiswoode.     The  Syllabus  of  Chemistry  may  be  had  separately. 

2  For  references  and  further  discussion  of  the  nature  study  plan,  see 
Heuristic  Method,  Chapter  IV.,  Section  IV.  (p.  105). 

3  The  Elementary  ( 1900)  and  Advanced  ( 1899)  Syllabuses  are  published 
by  Whittaker  &  Co.  (London). 


58        THE  INTRODUCTION  OF  THE  SUBJECT 

examinations  for  admission  to  most  colleges,  since  they  would 
probably  know  nothing  of  equations  or  the  atomic  theory. 
Their  work,  in  spite  of  its  excellence,  would  lack  some  of  the 
conventional  signs  which  usually  mark  a  knowledge  of  chemistry, 
and  sometimes  take  the  place  of  it.  The  study  of  them,  how- 
ever, will  afford  to  the  teacher  a  valuable  demonstration  of  the 
application  of  pedagogical  principles  to  the  study  of  chemistry. 
The  teacher  fresh  from  the  college  or  university,  especially  if 
he  has  been  highly  trained  in  chemistry,  is  apt  to  have  forgotten 
the  almost  innumerable  steps  by  which  he  reached  his  knowl- 
edge of  the  science,  and  to  give  his  pupils  work  which  assumes 
this  knowledge  rather  than  instruction  which  will  confer  it. 
Under  such  circumstances  their  acquisition  of  the  subject 
becomes  purely  mechanical,  and,  in  the  highest  sense  of  the 
term,  wholly  uneducative. 

The  second  of  the  three  guiding  principles  in  the  arrangement 
of  the  introductory  work,  the  theoretical,  is  illustrated  more  or 
Theoretical  ^ess  clearly  in  a  number  of  books.  The  idea  is 
Method.  typically  presented  in  Dr.  Torrey's  Elementary 

Studies  in  Chemistry}-  When  he  reaches  the  first  chemical  ex- 
periments (p.  62),  after  introductory  work  dealing  exclusively 
with  physical  properties,  he  proceeds  rapidly,  through  the  study 
of  combining  proportions  by  volume,  with  water  and  hydrogen 
chloride  as  the  concrete  materials,  to  the  statement  of  Avogadro's 
hypothesis  (p.  101)  and  the  consequences  which  follow  from  it. 
The  intervening  matter,  while  it  does  not  take  the  shortest 
course  possible  towards  this  goal,  nevertheless  is  lightened  of 
much  of  the  material  usually  treated  in  connection  with  the 
chemistry  of  oxygen,  hydrogen,  and  water,  in  order  that  the 
development  of  the  theory  may  not  be  impeded.  After  Avo- 
gadro's hypothesis  has  been  disposed  of,  a  larger  proportion  of 
general  chemical  work  begins  to  appear,  while  at  the  same  time 
formulae  and  atomic  weights  are  discussed.  Almost  all  of  the 
study  of  the  properties  of  the  elements  and  their  compounds 

1  Joseph  Torrey.  Elementary  Studies  in  Chemistry.  New  York. 
Henry  Holt  &  Co.  1899. 


THE  INTRODUCTION  OF  THE  SUBJECT       59 

thus  follows  the  theoretical  matter.  The  recent  work  of  Pro- 
fessor Young 1  is  arranged  similarly  on  the  same  general  princi- 
ple so  far  as  the  theoretical  part  is  concerned.  The  facts 
employed  up  to  the  end  of  the  development  of  the  theory 
(p.  89)  are  selected  at  random  from  various  parts  of  the  subject, 
and  in  consequence  solely  of  the  readiness  with  which  they  fur- 
nish experimental  support  for  the  theory.  The  systematic  treat- 
ment of  the  elements  then  follows.  Professor  Freer's  elementary 
work 2  resembles  these  books  in  placing  the  logical  development 
of  the  theory  in  the  foreground,  with  the  employment  of  a  mini- 
mum of  selected  facts,  and  differs  from  them  only  in  that  the 
treatment  of  the  rest  of  the  science  is  much  briefer,  and  the 
whole  ground  covered  much  less  extensive. 

The  third  principle  which  has  been  mentioned  as  affecting  the 
arrangement  of  the  work,  the  historico-systematic,  is  commonly 
associated  with  the  second,  and  the  presentation  of  . 

the  elements  one  by  one  is  usually  found  in  com-  Systematic 
bination  with,  and  as  a  modifying  factor  in,  the  e 
application  of  the  second  principle.  The  well-known  books  by 
Professor  Remsen8  and  Dr.  Newell,4  however,  illustrate  very 
well  the  continuous  development  of  the  principles  along  with  an 
arrangement  of  the  material  in  the  normal  order.  The  two  run 
side  by  side,  and  the  more  theoretical  portions  are  taken  up 
at  convenient  intervals  without  any  effort  to  introduce  each  at 
the  earliest  moment  at  which  this  is  theoretically  possible. 
Professor  Newth,  in  his  Elementary  Inorganic  Chemistry;'  pur- 
sues essentially  the  same  plan.  The  connection  between  experi- 
ment and  inference  is  worked  out  systematically  with  admirable 

1  A.  V.  E.  Young.     The  Elementary  Principles  of  Chemistry.     New 
York,  D.  Appleton  &  Co.     1901. 

2  P.  C.  Freer.     The  Elements  of  Chemistry.     Boston,  Allyn  &  Bacon. 
1895. 

3  Ira  Remsen.    Introduction  to  Chemistry  (Briefer  Course,}.    New  York, 
Henry  Holt  &  Co.     London,  Macmillan.     1893. 

4  Lyman  C.  Newell.     Experimental  Chemistry.    Boston,  D.  C.  Heath 
&  Co.     1900. 

5  G.  S.  Newth.     Elementary  Inorganic  Chemistry.    London  and  New 
York,  Longmans,  Green  &  Co.     1899. 


60       THE  INTRODUCTION  OF  THE  SUBJECT 

clearness.  The  theory  is  introduced  at  suitable  intervals  with- 
out haste  and  at  the  same  time  without  undue  delay.  The 
report  of  the  Committee  of  Nine  of  the  New  York  State  Science 
Teachers'  Association1  contains  a  detailed  outline  of  intro- 
ductory work,  in  which  the  same  combination  of  these  prin- 
ciples of  arrangement  is  observed. 

The  combination  of  the  second  principle  with  the  first  may 
be  seen  in  the  late  Professor  Cooke's  Laboratory  Practice? 
Ordinarily  the  theory  is  consistently  developed  after  certain 
physical  properties  and  manipulations  have  been  studied,  but 
here  the  rate  of  its  development  is  modified  by  the  effort  to 
combine  with  this  much  experimental  work  on  a  variety  of  ma- 
terials. The  difference  from  the  treatment  last  described  lies 
in  the  fact  that  this  chemical  experience  is  afforded,  not  by  the 
more  or  less  systematic  study  of  the  elements,  but  by  handling 
a  number  of  miscellaneously  selected  topics.8 

c.  The  Present  Ideal  of  the  Secondary  School  Course  in  Chem- 
istry :  —  Of  the  various  plans  outlined  above,  each  is  admirable 
Prevailing  m  ^ts  wav-  Each  has  advantages  for  certain  pur- 
Ideal,  poses.  It  remains  for  the  teacher  to  decide  which 
is  most  likely  to  suit  the  case  of  his  particular  set  of  pupils.  Nor 
need  the  choice  of  a  book  wholly  determine  the  kind  of  instruc- 
tion to  be  given,  although  it  must  influence  it  largely.  At  present 
the  prevailing  tendency  in  American  secondary  schools  seems 
to  be  towards  the  use  of  the  historico-systematic,  if  not  the 
theoretical  style  of  book.  At  least  the  recent  works  seem  to 

1  High  School  Bulletin  No.  7.     Albany,  N.  Y.,  The  University  of  the 
State  of  New  York.     By  post  35  cents.     This  bulletin  contains  so  much 
suggestive  matter  of  the  highest  interest  to  the  teacher  of  chemistry, 
aside  from  this  report,  that  the  reader  should  not  fail  to  obtain  it. 

2  J.  P.  Cooke.     Laboratory  Practice.     New  York,  D.  Appleton  &  Co. 
1891. 

3  Amongst  the  other  elementary  text-books  whose  methods  are  worthy 
of  study  are :  J.  E.  Reynolds.     Experimental  Chemistry  for  Junior  Stu- 
dents;  Part  I.,  Introductory;  Part    II.,  Non-metals ;  Part  III.,  Metals. 
Longmans,    Green   &    Co.      1897.     J.  Walker.     Elementary   Inorganic 
Chemistry.     Bell  &  Sons.     1902.    Henry  Roscoe.    Lessons  in  Elementary 
Chemistry.     Macmillan.     1890.     Storer  and  Lindsay.     Manual  of  Chem- 
istry.    American  Book  Company.     1894. 


THE  INTRODUCTION  OF  THE  SUBJECT      6 1 

emphasize  these  conceptions  in  their  selection  of  material  and 
method  of  arrangement.  Observation  of  the  work  of  many 
schools  confirms  this  belief.  It  is  evidently  a  prominent  aim  of 

the  teacher   at  the  present  day  to  give  his  Duoils 

,    3  r  1         Treatment, 

a  well-rounded  account  of  chemistry  as  a  science ;  Academic  and 

to  give  him  a  bird's-eye  view  of  the  science  as  an  r°rmah 
organized  system  of  knowledge  ;  in  fact,  to  show  him  an  outline 
plan  of  the  results  of  the  science  as  they  appear  to  the  chemist 
himself.  With  this  purpose  in  view,  Avogadro's  hypothesis 
and  its  consequences,  formulae,  and  equations  (often  even 
graphic  formulae),  and  many  somewhat  artificial  experiments 
with  strange  substances  have  to  play  a  conspicuous  part  in  the 
instruction. 

There  can  be  no  question  of  the  value  of  a  well-ordered  out- 
line knowledge  of  the  whole  science  for  the  understanding  of 

its  parts.     But  an  outline  or  map  of  an  extensive  _ 

r  Course  often 

territory  is  not  an  end  in  itself.  The  sketch  is  covers  too 
chiefly  useful  to  those  who  know  the  country  first  m 
hand  and  can  fill  in  from  their  own  experience  the  detail  of 
many  parts  and  so  form  a  true  appreciation  of  the  whole.  It  is 
the  knowledge  of  this  detail  which  constitutes  a  genuine  ac- 
quaintance with  the  subject  of  the  outline.  It  is  thus  unfortu- 
nate if  the  effort  to  give  a  systematic  plan  of  the  subject  is 
allowed  to  occupy  the  foreground,  while  the  method  and  detail 
of  the  science  are  suppressed  by  lack  of  time.  It  is  important 
therefore  pointedly  to  call  attention  to  a  possible  danger  in  this 
direction.  The  extensiveness  of  the  field  covered  by  the  book 
tempts  one  to  make  a  superficial  rush  through  the  whole  subject 
instead  of  taking  time  for  a  detailed  study  of  the  fundamental 
things  of  the  science.  Thus  the  hypothesis  just  mentioned  is 
indeed  fundamental,  in  a  sense.  But  behind  it  and  on  every 
side  of  it  there  is  something  without  which  it  is  merely  an  empty 
phrase,  and  that  is  the  ability  to  understand  and  reason  about 
chemical  problems  as  they  present  themselves  in  the  laboratory. 
The  behaviour  of  concrete  substances  and  mixtures  of  substances 
in  real  test-tubes  and  flasks  and  the  phenomena  around  us  in 


62         THE  INTRODUCTION  OF  THE  SUBJECT 

nature  must  be  understood  before  more  abstract  matters  ac- 
quire any  significance. 

The  point  is  that  there  are  few,  very  few,  secondary  schools 
in  which  the  time  allotted  to  chemistry  permits  treating  both  of 
these  aspects  adequately.  I  hesitate  to  quote  experience  in 
higher  institutions  in  discussing  school  work.  What  a  univer- 
sity student  can  do,  in  many  cases  the  school  pupil  cannot  do. 
Yet,  what  a  university  student  cannot  do,  with  the  advantages 
of  maturity  and  preparation  which  he  possesses,  must  surely 
be,  a  fortiori,  beyond  the  pupil  in  the  high  school.  I  find 
that  more  than  a  hundred  hours  (of  60  minutes)  in  class- 
room and  laboratory  are  required  for  the  introduction  to  the 
subject.  In  the  course  of  this,  a  beginning,  and  only  a  be- 
ginning, is  made  in  learning  to  observe ;  the  theory  up  to 
and  including  Avogadro's  hypothesis  is  taught ;  and  a  few  ele- 
ments and  compounds  are  studied  in  a  very  elementary  way. 
All  that  can  be  covered  in  this  time,  besides  introductory  matter, 
is  the  chemistry  of  oxygen,  hydrogen,  water,  chlorine,  hydrogen 
chloride,  air,  and  nitrogen  (the  element  only).  It  would  be 
desirable  to  give  even  more  time  to  this  seemingly  meagre  pro- 
gramme. Indeed  more  would  be  given  if  the  imperative  necessity 
of  covering  the  whole  subject  in  outline  within  a  total  of  325 
hours  did  not  compel  the  adoption  of  a  more  rapid  gait  at  the 
expense  of  thoroughness.  Now  100  hours  is  half  or  more  than 
half  the  whole  time  allotted  to  the  subject  in  most  secondary 
schools.  In  giving  the  same  extent  of  work  with  the  pupils  of 
a  secondary  school  I  should  be  compelled  to  occupy  an  even 
longer  time,  and  all  hope  of  covering  the  subject  would  have  to 
be  given  up. 

More  rapid  progress  through  the  science  can  be  had  only  by 
substituting  the  memorizing  of  results  for  genuine  study  of  chemi- 
The  intensive  ca^  problems.  Learning  chemistry  as  it  is  and  mak- 
Method.  mg  a  rapid  survey  are  two  things  which,  under  the 

conditions  imposed  by  the  programmes  of  secondary  schools, 
are  incompatible.  What  is  meant  by  genuine  study  of  chemi- 
cal problems?  Let  us  take  an  example.  Suppose  we  learn 


THE  INTRODUCTION  OF  THE  SUBJECT      63 

that  hydrogen  burns  in  air  and  forms  water,  and  illustrate  the 
fact  by  burning  a  jet  of  hydrogen  in  the  laboratory  and  holding 

a  cold  beaker  over  the  flame.     This  exercise  has 

,,  ,  ,       ,       r  ,  Illustrations, 

the  appearance  of  having  taught  the  tact,  and  we 

go  off  in  the  belief  that  the  pupil  thoroughly  understands  all 
about  it.  If,  however,  we  overhaul  his  conceptions,  we  soon 
find  that  we  have  conventionalized  the  experiment  and  the 
result  has  been  learned  as  a  purely  mechanical  acquisition. 

To  test  this  statement,  take  the  class  after  this  exercise, 
extinguish  the  jet  of  burning  hydrogen,  hold  a  cold  beaker 
against  the  jet  of  unlighted  gas,  and  ask  what  the  class  thinks 
of  the  moisture  which  the  gas  is  seen  to  deposit  even  in  this 
condition.  In  a  large  class  a  few  will  suggest  that  the  water 
comes  from  the  union  of  the  hydrogen  with  the  oxygen  of  the 
air,  —  showing  that  they  have  failed  to  appreciate  the  signifi- 
cance of  the  lighting  of  the  jet.  Others  will  think  it  comes 
from  condensation  of  moisture  in  the  atmosphere,  although 
they  can  give  no  explanation  of  how  this  happens.  I  have  not 
yet  encountered  a  class  of  beginners  in  the  university  in  which 
a  single  member  is  to  be  found  who  can  suggest  the  correct  ex- 
planation, so  little  are  students,  even  well-prepared  and  intelli- 
gent ones,  able  to  apply  the  knowledge  of  physics  they  possess. 
Further  questioning  shows  that,  although  the  whole  preparation 
of  the  experiment  had  previously  been  done  by  the  pupils  them- 
selves, and  attention  had  been  drawn  to  the  heat  developed  by 
the  action,  not  one  realized  spontaneously  that  his  flask  con- 
tained a  liquid  which  was  warm  and  consisted,  to  the  extent  of 
80  per  cent,  of  water  through  which  the  hydrogen  was  passing. 
The  bare  skeleton  of  the  action,  as  it  appears  in  the  equation 
Zn  -f  H2SO4  -*ZnSO4  +  H2,  seemed  to  be  all  that  their  minds 
had  consciously  grasped  of  the  whole  paraphernalia  of  the  action. 

It  is  only  after  a  thorough  discussion  in  which  attention  has 
been  called  to  the  details,  that  the  pupil  realizes  that  the  first 
condensation  of  moisture  was  quite  inconclusive  as  a  proof  that 
water  was  formed  by  the  union  of  hydrogen  and  oxygen,  sees 
the  need  of  drying  the  gas,  and  finally  learns  that  chemical 


64%    THE  INTRODUCTION  OF  THE  SUBJECT 

"~'"\ 

work  includes  far  more  and  far  more  important  things  than  put- 
ting together  the  materials  stated  in  the  equation.  Now  this 
sort  of  experience  can  be  duplicated  in  almost  every  action 
studied,  and  it  must  be  constantly  repeated  in  a  thousand  forms 
before  any  intelligence  about  chemical  work  can  be  developed. 
But  this  sort  of  work  takes  time  which  might  otherwise  be 
devoted  to  passing  on  to  the  acquisition  of  a  quasi-knowledge 
of  new  actions. 

It  is  doubtless  assumed  by  the  writers  of  the  systematic  variety 
of  treatises,  that  the  thorough  development  of  all  sides  of  each 
experiment  will  be  brought  out  by  the  teacher.  They  furnish 
the  skeleton,  and  the  teacher  does  the  heavier  share  of  the  work. 
The  most  of  the  real  chemistry  is  between  the  lines.  So,  as 
has  been  said,  the  character  of  the  book  need  not  determine 
the  character  of  the  instruction.  A  skeleton  book  need  not 
lead  to  an  attenuated,  fleshless,  academic  treatment  of  the  sub- 
ject .in  the  class.  But  the  inexperienced  teacher,  and  it  is  for 
him  chiefly  that  this  is  written,  will  find  that  it  takes  much 
thought  and  experience  to  extract  the  meat  from  the  work, 
that  the  skeleton  in  the  book  may  be  fitly  clothed  withal,  and 
that  there  is  a  constant  temptation  to  treat  the  skeleton  itself  as 
if  it  were  the  chief  dish  of  the  feast. 

There  must  be  some  reason  for  the  tendency  to  make  school 
text-books  of  chemistry  more  and  more  academic.  It  must  be 
Why  is  the  that  some  essential  element  in  secondary  education 
^schools'  would  be  lacking  if  the  formal  survey  of  the  science 
so  Formal?  were  not  conspicuous,  or  its  prominence  as  a  char- 
acteristic of  school  chemistries  would  not  be  so  great.  Perhaps 
the  key  may  be  found  in  the  use  to  which  the  chemistry,  or  the 
training  it  furnishes,  is  to  be  put  in  after  life.  This  test  ought 
to  furnish  the  explanation  of  all  peculiarities  of  secondary  school 
work.  Some  of  the  pupils  go  to  college,  some  become  teachers 
in  grammar  and  grade  schools,  the  great  majority  go  into  the 
affairs  of  business  or  professional  life.  What  purpose  can  for- 
mal chemistry  serve  for  each  of  these  classes  ? 

To  the  last  a  knowledge  of  formal  chemistry,  which  is  not 


THE  INTRODUCTION  OF  THE  SUBJECT      65 

also  much  more  than  this,  cannot  be  of  great  use.     On  the 
other  hand,  a  quick  perception  of  conditions,  ability  to  reason 
surely  about   the  causes   of  physical   phenomena,   chemistry  in 
capacity  to  study  materials  and  to  devise  means  of  Preparation 
accomplishing  definite  ends  with  them  and,  in  the 
broader  view,  a  confirmed  habit  of  getting  to  the  bottom  of 
everything  that  is  observed,  will  be  invaluable.     It  will  be  of 
for  more  use  than  an  array  of  picked  information  which  all 
soars  a  little  above  the  plane  of  experience  as  we  find  it,  and 
has  not  been  brought  down  to  the  every-day  level. 

Again,  the  teacher  in  the  lower  schools  gives  instruction  in 
elementary  science.  But  here  a  formal  knowledge  of  chemistry 
only  hampers  her,  unless  she  has  happened  to  have  Chemistryin 
the  opportunity  to  go  further  into  the  subject.  The  Preparation 
chemistry  of  the  grades,  so  far  as  their  nature-study  f 
work  can  be  said  to  include  chemistry,  must  not  be  consciously 
chemistry  at  all.  A  knowledge  of  three  distinct  ways  of  making 
chlorine  and  the  ability  to  name  the  fundamental  laws  of  chem- 
istry will  not  be  of  much  assistance.  The  study  is  approached 
from  an  entirely  different  side.  TFor  example,  what  are  leaves 
made  of  and  where  do  they  go  when  they  disappear  every 
autumn  ? l  The  high-school  text-books  do  not  tell  us  how  to 
lead  the  child  to  some  comprehension  of  this  latter  wonderful 
natural  fact.  We  may  take  two  equal  heaps  of  leaves  and 
weigh  one  and  keep  the  other  for  reference.  Then  we  dry  the 
weighed  leaves.  For  small  children  we  condense  the  moisture 
that  comes  off  and  show  it.  Thus  we  have  a  certain  weight  of 
dried  vegetable  matter  and  a  certain  weight  of  water,  both  of 
which  can  be  handled  and  compared  with  the  undried  speci- 
men. Then  we  burn  the  dry  leaves  and  get  a  certain  weight 
of  ash,  and  a  loss  in  weight  represented  by  the  burnt  mate- 
rial. Then  we  treat  the  ash  with  water,  and  part  dissolves, 
and  is  recovered  by  evaporation.  Part  remains  insoluble. 
Thus  we  lay  bare  the  nature  of  leaf  material.!  The  child  sees 

1  From  Jackman's  Nature  Study  for  Grammar  Grades  (Macmillan), 
chapter  VIII. 

5- 


66        THE  INTRODUCTION  OF  THE  SUBJECT 

also  that  the  ash  part  came  from  the  soil,  the  water  from  rain 
or  other  moisture  of  the  soil.  The  subject  can  be  pursued 
further  if  it  seems  desirable.  My  point  is  that  while  intelligent 
teaching  of  this  sort  of  thing  will  be  assisted  by  a  systematic 
knowledge  of  chemistry,  it  will  be  quite  impossible  if  the  knowl- 
edge of  chemistry  was  of  the  formal,  equation-loving  sort  and 
nothing  more.  Evidently  the  too  academic  variety  of  chemistry 
is  not  intended  to  help  the  teacher  in  the  grades. 

Finally,  can  it  be  that  the  teaching  of  chemistry  in  secondary 
schools  has  been  modelled  to  suit  the  supposed  need  of  the 
Chemist  in  PUP^  w^°  ^s  SomS  to  college,  and  that  the  needs 
Preparation  of  the  vast  majority  who  do  not  go  to  college  are 
w  College.  .^  Danger  of  being  sacrificed  ?  It  would  be  a  pity 
if  that  were  the  case.  There  is  no  reason  why  the  college 
should  demand  a  knowledge  of  formal  chemistry  for  admission. 
Any  good  chemical  instruction  which  really  teaches  chemistry 
of  some  kind  should  be  gladly  accepted.  Of  course  a  knowl- 
edge of  how  to  reason  and  how  to  work  intelligently  is  difficult 
to  test  by  examination,  while  the  presence  of  a  knowledge  of 
formal  chemistry  can  be  readily  ascertained.1  But  if  the  intel- 
ligent knowledge  of  chemistry  is  more  valuable  for  other  pur- 
poses, and  at  least  as  valuable  to  the  college  entrant,  it  is  the 
business  of  the  college  to  find  some  way  of  testing  it.  It  is 
much  to  be  feared  that  the  college  ideals  of  what  constitutes  a 

1  The  various  existing  reports  describing  courses  in  chemistry  for 
secondary  schools  are  perhaps  in  part  responsible  for  perpetuating  the 
impression  that,  whatever  else  is  desirable,  a  formal  survey  of  the  science 
is  indispensable.  It  is  relatively  so  easy  to  give  a  brief  yet  comprehen- 
sive list  of  topics,  and  so  difficult  to  describe  effectively  the  spirit  and 
manner  in  which  the  instruction  is  to  be  carried  out,  that  the  former 
never  fails  to  put  in  an  appearance,  while  the  latter  is  slighted.  The  list 
may  be  suggestive  and  valuable,  but  if  it  is  unaccompanied  by  a  full  dis- 
cussion of  how  the  teaching  is  to  be  done,  occupying  a  space  which,  to 
represent  the  relative  importance  of  the  two  parts,  would  have  to  be  ten, 
or  even  a  hundred  times  more  extensive,  the  impression  conveyed  by 
the  report  as  a  whole  must  be  misleading.  The  fact  that  preparing  and 
securing  the  passage  of  such  an  extensive  report  are  well-nigh  imprac- 
ticable is  the  only  excuse  that  can  be  found  for  the  way  in  which  the 
crucial  part  of  the  task  has  hitherto  been  avoided. 


THE  INTRODUCTION  OF  THE  SUBJECT       67 

genuine  knowledge  of  chemistry,  which  are  themselves  much  in 
need  of  reformation,  have  been  permitted  to  influence  the  kind 
of  chemistry  taught  in  the  schools  to  far  too  great  an  extent. 

In  what  has  been  said  above  there  is  danger  that  I  may  be 
misunderstood.  No  one  can  doubt  the  pre-eminent  value,  the 
absolute  indispensability  to  the  chemist,  of  a  systematic  view  of 
the  science.  But  an  attempt  really  to  give  this  view  in  any 
genuine  way,  when  the  basis  is  lacking,  must  be  futile.  Along 
with  this  view,  the  chemist  has  also  at  his  command  all  the 
details  which  have  gone  to  the  making  chemistry  in  the  past 
and  which  make  chemistry  for  him  a  living  reality.  I  am  there- 
fore raising  the  question  whether  putting  the  broad  sketch  of 
the  whole  in  the  foreground,  and  leaving  the  details  to  the 
teacher  and  to  chance,  is  not  a  reversal  of  the  proper  order. 
Some  of  both  must  be  given.  But  the  technique  of  experi- 
ment, observation,  and  induction,  and  the  habit  of  using  it 
come  first. 

It  was  with  thoughts  of  this  sort  in  mind  that  emphasis  was 
laid  on  books  of  the  nature-study  variety.  Much  of  their  spirit 
may  be  infused l  into  teaching  which  professes  to  follow  one  of 
the  other  plans.  Adaptation  to  the  point  of  view  of  the  begin- 
ner will  demand  such  an  infusion,  if  the  instruction  is  not  to 
be  altogether  artificial.  We  cannot  approach  a  class  with  the 
idea  that  here  is  a  certain  outline  of  work  to  be  done,  which 
has  been  selected  because  its  importance  is  evident  to  the 
mature  mind  of  the  chemist,  and  regard  the  pupil  as  being 
there  to  receive  the  dose.2  The  case  is  rather  that  the  pupils 
are  there  to  be  educated  and  assisted  in  development,  and  the 
work  must  be  adapted  to  their  preparation  and  needs. 

At  the  same  time  this  book  has  not  been  written  to  advocate 
a  new  kind  of  chemistry,  but  to  assist  the  teacher  who  is  giving 
the  kind  of  chemistry  which  is  at  present  demanded.  So  we 
shall  assume  for  the  most  part  in  what  follows  that  one  of  the 

1  See  the  paragraph  on  the  attitude  to  be  cultivated   in  the  pupil 
under  Instruction  in  the  Laboratory,  chapter  IV.,  section  IV.  (p.  105). 

2  See  May  M.  Butler,  SCHOOL  REVIEW,  X.,  (1902),  52. 


68        THE  INTRODUCTION  OF  THE  SUBJECT 

more  or  less  systematic  texts  is  being  used,  and  simply  try  as 
occasion  offers  to  show  how  the  instruction  based  upon  it  may 
be  adapted  to  give  the  most  benefit. 

To  sum  up  our  conclusions,  the  study  of  chemical  change, 
the  generalization  of  the  features  which  it  presents,  and  the  ac- 
Concluskms  quisition  of  the  habit  of  applying  the  knowledge 
introfiSory  thus  acclm'red»  are  the  business  of  the  student  of 
Work.  chemistry.  In  assisting  him  to  a  mastery  of  the 

science,  the  first  thing  is  to  lay  a  solid  foundation  in  the 
knowledge  of  the  detail  of  observation.  The  second  thing  is 
to  lead  him  up  to  generalization,  for  without  this  the  work  will 
not  be  scientific.  The  third  thing  is  to  exercise  him  in  applica- 
tion, otherwise  the  work  will  not  be  useful.  Ordinarily  the  work 
is  controlled  in  the  fourth  place  by  an  effort  to  approach  the  sys- 
tematic arrangements  of  the  elements,  or  at  all  events,  sooner  or 
later,  to  reach  this.  Finally,  it  is  undoubtedly  useful  to  combine 
these  objects  with  the  presentation  of  much  of  the  early  matter 
in  the  historical  order. 

Most  of  these  objects  are  readily  attained  by  selecting  for 
early  treatment  actions  in  which  air  plays  a  part.  Historically, 
the  discovery  of  oxygen  by  Priestley  and  Scheele,  and  the  proof  of 
its  presence  in,  and  responsibility  for  the  chief  properties  of  the 
air  by  Lavoisier,  coming  as  it  did  at  a  time  when  chemistry  was 
just  crystallizing  into  a  science,  point  to  experiments  on  the 
action  of  air  as  particularly  significant  in  an  historical  point  of 
view.  The  study  of  oxygen,  a  gas,  enables  us  rapidly,  if  we 
choose,  to  approach  the  theoretical  portion  of  the  science,  and, 
at  the  same  time,  the  familiar  nature  of  its  chemical  effects 
makes  them  suitable  for  introductory  work. 

We  assume  then  that  some  simple  and  more  or  less  familiar 
facts,  some  of  them  probably  connected  with  the  action  of  the 
air,  will  be  presented  in  the  beginning  to  the  pupil.  Some  of 
these  may  be  examined  by  him  personally  in  the  laboratory ; 
others  may  be  shown  him  by  the  teacher.  It  is  impossible  for 
us  here  to  describe  in  detail  the  method  which  the  teacher  will 
pursue  in  bringing  out  the  significance  of  what  is  seen  by  call- 


THE  INTRODUCTION  OF   THE  SUBJECT       69 

ing  attention  to  the  detail  of  observation  and  leading  the  pupil 
to  the  interpretation  of  each  detail.  Illustrations  of  the  method 
to  be  used  will  be  found  admirably  given  in  Perkin's  work 
already  mentioned.  Professor  Richards  gives  some  instructive 
examples  in  the  Harvard  pamphlet  of  requirements  in  chem- 
istry.1 Many  laboratory  manuals  also  develop  the  method  of 
instruction  with  considerable  fulness. 


III.     Earlier  Generalizations  of  a  Qualitative  Nature. 

The  first  thing  which  the  examination  of  several  chemical 
changes   reveals  is   that  a  total  alteration  in  all  the  physical 

properties  of  the  substance  takes  place.     This  is  a 

*  .  .  .  ,  ,  .    .  ,.          First  Charac- 

feature  requiring  minute   and    careful   instruction,    teristlcof 


In  order  that  the  pupil  may  adequately  appreciate 
this  characteristic,  the  nature  of  the  various  physi- 
cal properties  which  are  interesting  to  the  chemist  must  be 
discussed  more  or  less  fully,  and  in  each  particular  case  the 
properties  of  the  body  or  bodies  before  chemical  change,  and 
the  new  properties  after  chemical  change,  must  be  carefully  and 
exactly  enumerated.  The  pupil  will  not  do  this  for  himself, 
and  without  it  his  ideas  must  remain  somewhat  hazy.  This  is 
advised  not  because  the  doctrinaire  treatment  of  this  conven- 
tional sign  of  chemical  change  is  particularly  helpful,  but  be- 
cause a  keen  appreciation  of  physical  details  is  at  the  basis  of 
all  chemical  work.  The  pupil  must  eventually  learn  to  recog- 
nise materials  by  their  physical  properties,  since  by  this  alone 
can  he  study  chemical  change  qualitatively. 

In  many  cases  the  study  of  physical  properties  is  treated  as  a 
separate  topic  before  any  chemical  change  is  introduced,  and 
there  is  certainly  justification  for  this  course,  even 
if  the  pupils   have  already  studied  the  science  of  of  Knowledge 
physics   itself.     There  are   many  physical  matters   ofphysics' 
important  to  the  chemist  which  are  not  treated  in  elementary 


1  Requirements  in  Chemistry  for  Entrance  to  Harvard  College.     Cam- 
bridge, published  by  the  University,  1900. 


70       THE  INTRODUCTION  OF  THE  SUBJECT 

physics.1  Every  teacher  of  chemistry  knows  the  mistakes  which 
the  beginner  makes  when  told  to  evaporate  any  substance  in 
order  to  attain  crystals  for  examination.  The  pupil  is  utterly 
innocent  of  any  knowledge  of  the  conditions  under  which  crys- 
tals are  formed,  and  usually  does  not  even  recognise  that  the 
amorphous  mass  he  obtains  by  violent  boiling  over  a  naked 
flame  is  not  the  required  crystalline  product.  And  this  is  only 
one  example  out  of  many  which  might  be  adduced  to  show  that 
a  knowledge  of  physical  properties  which  remain  unconsidered 
in  school  physics  is  an  indispensable  part  of  the  equipment  of 
the  pupil  in  chemistry.  The  necessity  of  attention  to  this  mat- 
ter has  already  been  emphasized  (pp.  30-33  and  39),  and  its  ex- 
treme importance  alone  justifies  our  recurrence  to  the  subject. 

This  study  of  physical  change  leads  to  the  familiar  general- 
ization2 that  every  physical  property  is  altered,  and  that  the 
alteration  is  usually  permanent.  Most  frequently  the  matter 
is  made  clearer  by  contrast  with  physical  change.  It  is  advis- 
able also  to  cite  familiar  instances  of  each  kind  of  change. 

The  study  of  the  facts  in  connection  with  the  first  few  ex- 
periments next  reveals  the  nature  of  chemical  change.  Some 
Second  Char-  material  has  come  out  of  combination  or  gone  into 
acteristic.  combination.  In  other  words,  the  great  change  in 
physical  properties  is  accompanied  by  a  change  in  composition. 
If  the  experiments  on  which  this  conclusion  is  founded  have  been 
properly  selected,  they  will  incidentally  lead  to  the  classification 
of  changes  in  composition  into  the  three  common  kinds.  The 

1  In  Tilden's    Teaching  of  Elementary   Chemistry,    8— n,  and    more 
especially  in  the  work  of  Perkin  and  Lean  which  we  have  already  (p.  56) 
mentioned,  22-125,  will  be  found  laboratory  instructions  covering  a  large 
number  of   experiments  on  those  physical   properties,  familiarity  with 
which  is  most  important  in  chemical  work. 

2  The  two  or  three  facts  actually  in  the  hands  of  the  pupil  do  not,  of 
course,  strictly  speaking,  justify  generalization.      No  generalization  in  a 
science  deserves  the  name  unless  it  is  founded  upon  an  immense  range 
of  facts.     The  teacher   must  therefore  indicate  the  direction  in   which 
numerous  other  facts  of  the  same  kind  lie,  in  such  a  way  that  the  pupil 
readily  appreciates  their  nature,  and  feels  satisfied  with  the  general  prin- 
ciple deduced.     The  conscientious  development  of  a  single  generaliza- 
tion might  otherwise  occupy  the  whole  year. 


THE  INTRODUCTION  OF  THE  SUBJECT   •    /I 

first   experiments  in  chemical  change  are   discussed  again  in 
i this  connection. 

The  pupil's  attention  may  next  be  drawn  to  the  production 
or  disappearance  of  heat  in  connection  with  some  of  his  illus- 
trations of  chemical  change.  Special  experiments  Third  char- 
may  even  be  introduced  to  show  that  in  like  man-  acteristic. 
ner  light  and  electricity  may  be  consumed  or  produced  in  a 
similar  way.  This  is  not  of  course  the  place  in  which  to  dis- 
cuss energy,  but  it  furnishes  a  convenient  opportunity  at  least  f 
for  drawing  the  attention  of  the  pupil  to  the  fact  that  all 
chemical  change  is  accompanied  by  energy  change  of  some 
kind.  Perhaps  even  the  economic  importance  of  this  in  con- 
nection with  the  steam-engine  and  the  storage  battery  may  be 
referred  to.  If  he  has  already  studied  physics,  the  tendency 
to  the  dissipation  of  energy,  which  a  chemical  system,  in  com- 
mon with  any  physical  one,  exhibits,  may  repay  notice.  In  any 
case,  none  of  the  subjects  touched  at  this  stage  can  possibly  be 
treated  fully  or  become  a  section  of  the  subject  complete  in  it- 
self. Usually,  recurring  to  the  same  subject  at  intervals,  and 
adding  a  little  each  time,  will  be  more  effective,  when  the  ques- 
tion is  an  abstract  one,  than  a  complete  treatment  of  it  at  any 
stage.  The  pupil  becomes  gradually  accustomed  to  thought 
about  the  subject,  and  thus  does  not  experience  the  difficulty 
and  perhaps  disgust  with  which  a  sudden  presentation  of  abstract 
ideas  may  otherwise  affect  him. 

Aside  from  the  three  main  features  which  we  have  men- 
tioned, there  are  matters  which  may  be  described  as  minor,  and 
which  yet  are  exceedingly  important  and  soon  begin  Qth  rMinor 
to  obtrude  themselves  upon  our  notice.  There  is,  but  Important 
for  example,  the  necessity  for  contact  in  order  that  Trutlls> 
chemical  action  may  occur.  It  is  long  before  the  pupil  realizes 
that  putting  two  materials  in  the  same  test-tube  is  not  the  equiva- 
lent of  giving  them  every  opportunity  for  interaction.  If,  for 
example,  the  experiment  is  to  place  powdered  potassium  iodide 
in  a  test-tube,  add  concentrated  sulphuric  acid  and  observe  the 
result,  one  pupil  will  fulfill  the  directions  to  the  letter,  while  his 


72         THE  INTRODUCTION  OF  THE  SUBJECT 

neighbour  may  use  large  crystals  of  the  substance  instead  of 
powdering  them.  Thus  while  the  former  obtains  a  violent  action 
in  the  cold,  the  latter  may  decide  that  practically  nothing  hap- 
pens. It  requires  most  persistent  discussion  to  lead  students 
to  realize  that,  unless  means  is  taken  to  permit  complete  access 
of  every  part  of  each  substance  to  every  part  of  the  other,  the 
best  conditions  for  chemical  change  have  not  been  fulfilled,  and 
that,  without  thorough  mixing,  chemical  action  is  as  little  to  be 
expected  as  if  the  substances  had  been  in  different  test-tubes 
instead  of  the  same  one.  Another  matter  worthy  of  notice  is 
the  great  increase  in  the  speed  with  which  a  chemical  change 
takes  place  when  the  temperature  is  even  slightly  elevated. 
This,  together  with  the  melting  or  other  assistance  to  contact 
which  heating  affords,  is  the  reason  for  its  effect  on  chemical 
change.  A  third  point,  which  for  the  present  is  of  minor  im- 
portance, is  the  fact  that  chemical  changes  are  often  carried  out 
with  incomparably  greater  ease  by  dissolving  the  substances  in 
water,  and  that  in  most  cases  of  this  kind  the  water  is  not  a 
factor  in  the  change.  It  is  only  by  noting  matters  like  these, 
in  the  many  various  ways  in  which  they  affect  chemical  change, 
that  the  pupils'  chemical  intelligence  can  be  slowly  developed. 

IV.     Further  Generalizations,  of  a  Quantitative  Character. 

The  basis  for  the  introduction  of  the  fundamental  quantita- 
tive laws  of  chemistry  may  soon  be  reached.  This  may  be 
found  partly  in  the  very  first  experiments,  and  partly  in  addi- 
tional ones  designed  more  specifically  for  the  purpose.  If  it 
is  desired,  the  systematic  development  of  the  subject-matter 
may  begin  at  this  point,  or  at  all  events  immediately  after  the 
first  of  the  following  principles.  This,  following  the  historical 
order,  will  probably  begin  with  a  more  formal  study  of  oxygen 
and  its  relation  to  air.  Or,  as  some  writers  prefer  to  arrange 
it,  hydrogen  may  precede  oxygen,  and  water  may  precede  air. 
We  shall  not  attempt  to  express  any  preference  in  regard  to 
the  particular  time  for  introducing  this  treatment  or  the  par- 


THE  INTRODUCTION  OF  THE  SUBJECT    .  73 

ticular  topic  with  which  it  shall  begin.  The  matter  is  largely 
one  depending  on  the  taste  of  the  teacher,  and  the  arrangement 
of  the  book  he  uses. 

The  first  of  these  generalizations  arises  naturally  in  answer  to 
the  question  whether,  in  the  changes  which  have  been  noticed, 
one  body  combines  with  another  and  alters  the  char-  Fourth  char- 
acter of  the  latter  without  adding  to  the  weight,  or  acteristic. 
whether  each  substance  takes  its  weight  with  it  into  combina- 
tion. This  being  answered  in  the  affirmative,  the  further  ques- 
tion arises  —  whether  this  occurs  absolutely  without  loss  or  gain, 
or  takes  place  with  some  slight  abatement  or  modification  of 
weight.  The  fact,  of  course,  is  that,  of  all  the  physical  prop- 
erties of  a  substance,  its  weight  is  the  only  one  which  it  is 
found  to  have  carried  with  it  through  any  number  of  chemical 
transformations.1 

It  must  be  clearly  explained  to  the  pupil  that  this  principle 
cannot  be  rigidly  established  without  an  immense  number  of 
experiments,  and  all  of  them  would  have  to  be  of  a  more 
exact  character  than  the  technical  skill  of  the  beginner  could 
furnish. 

Closely  associated  with  the  question  answered  by  the  previous 
law,  is  that  of  whether,  in  producing  the  same  compounds,  con- 
stant proportions  of  the  constituents  are  required.   Fifth  Char- 
The  answer  is  naturally  in  the  affirmative.  acteristic. 


1  Phrases  like  the  conservation  of  matter  or  of  energy,  if  used  at  all 
with  beginners,  should  be  defined  carefully  in  strict  harmony  with  their 
particular  experience,  or,  if  they  have  none,  at  least  with  conceptions  which 
can  most  readily  be  pictured  to  the  mind.  The  statements,  for  example, 
that  the  "  sum  total  of  each  kind  of  matter,"  or  "  of  all  the  energy  "  "  in  the 
universe  "  is  constant  are  too  remote  from  experimental  examination  to 
be  seen  to  have  any  relation  to  ordinary  experience.  It  may  be  remarked 
also  that  they  are  not  in  this  form  scientific"  statements,  but  metaphysi- 
cal speculations.  All  that  we  can  verify  by  experiment  is  the  fact  that 
in  physical  and  chemical  operations  on  a  limited  scale  the  matter  and 
energy  can  all  be  accounted  for,  and  we  have  no  evidence  that  any  is  lost 
or  gained.  The  more  abstract  mode  of  statement  leads  the  pupil  natu- 
rally to  think  that  these  laws  are  simply  dogmas.  Many  of  us,  having 
received  this  false  impression,  have  for  a  time  wondered  greatly  what 
the  origin  of  these  dogmas  was. 


74        THE  INTRODUCTION  OF  THE  SUBJECT 

As  before,  these  generalizations  will  be  illustrated  by  refer- 
ence to  every-day  experience  on  which  they  have  a  bearing. 
Generalization  is  not  an  end  in  itself.  It  is  simply  the  clear 
formulation  of  a  fact  preparatory  to  its  employment  for  illumi- 
nating our  experience.  Application  in  later  work  in  chemistry 
occurs  as  a  matter  of  course.  It  is  important,  however,  that 
the  employment  should  be  as  wide  in  range  as  possible.  We 
are  all  familiar  with  the  surprise  with  which  the  obviousness 
of  an  application  or  illustration  strikes  us  after  the  relation  has 
been  pointed  out  by  some  one  else.  Yet  it  is  chiefly  an  inde- 
pendent ability  to  apply  what  is  known  that  distinguishes  the 
scholar  from  the  prig.  The  mastery  of  the  generalizations  of 
chemistry  may  constitute  a  part  of  learning  in  a  narrow  sense  : 
to  have  digested  them  and  become  able  to  see  their  application 
to  remoter  facts  within  our  knowledge  is  education.  The 
possibilities  and  methods  of  application  are  discussed  more 
fully  under  classroom  instruction  (chapter  V.,  sections  a  and  e, 
pp.  129  and  138). 

In  connection  with  the  discussion  of  the  law  of  definite  pro- 
portions, the  question  of  the  actual  ratios  by  weight  in  some 
Measurement  smiP^e  chemical  compounds  will  naturally  come  up. 
of  Proportions  The  proportions  in  some  of  the  actions  already  no- 
ught. ^^  should  be  given  as  illustrations,  and  the  results 
expressed  by  percentage.  If  possible,  the  actual  carrying  out 
of  a  measurement  should  be  shown.  The  union  of  a  weighed 
amount  of  copper  with  oxygen,  for  instance,  is  a  suitable  ex- 
periment, for  it  requires  no  supervision.  Other  quantitative 
experiments  which  are  available  will  be  discussed  in  the  chap- 
ter on  the  laboratory  work. 

The  principle  of  multiple  proportions  may  fitly  follow.  As  a 
classroom  illustration,  the  reduction  of  cuprous  and  cupric 
Sixth  char-  oxides  by  hydrogen  will  be  found  easy,  provided 
acteristic.  pure  cuprous  oxide  can  be  obtained,1  as  failure  to 
get  good  results  is  almost  impossible. 

The  next  generalization  is  that  relating  to  reciprocal  propor- 

1  I  have  found  Kahlbaum's  most  satisfactory. 


THE  INTRODUCTION  OF   THE   SUBJECT       ?$ 

tions  (law  of  combining  weights).  For  its  development  a  num- 
ber of  actual  combining  proportions  and  equivalent  weights  are 
required,  and  may  be  tabulated  on  the  blackboard.  Seventh Char- 
The  study  of  the  numbers  which  a  suitable  series  acteristic. 
exhibits  brings  out  a  very  remarkable  fact  about  chemical  com- 
bination. This  may  be  stated  as  follows  :  If  we  take  any  ele- 
ment as  basis,  and  any  number  as  the  value  for  the  combining 
weight  of  that  element,  then  the  quantities  of  other  elements 
which  combine  with  this  amount,  or  are  equivalent  to  it  in 
chemical  combination,  have  this  property,  that  complete  com- 
bination of  the  elements  with  one  another  takes  place  when 
these  quantities,  or  simple  integral  multiples  of  them,  are  em- 
ployed, and  no  compounds  are  known  whose  composition  is 
not  in  harmony  with  this  rule.1 

This  relation  furnishes  us  with  a  set  of  combining  weights,  or 
rather,  by  varying  choice  of  the  basal  element  and  value  as- 
signed to  it,  an  indefinite  number  of  such  sets  of  weights.  It 
may  therefore  be  indicated  at  this  point  that  convenience  de- 

1  It  is  one  of  the  most  serious  defects  of  many  elementary  text-books 
that  they  do  not  formulate  this  principle  in  terms  of  its  experimental 
basis.  It  seems  sometimes  to  be  left  entirely  out,  and  its  consequences 
creep  in  unawares  under  the  cloud  of  dust  raised  by  the  atomic  theory,  or 
appear  in  the  use  of  equations  without  any  attempt  at  justification  of  the 
prodigious  logical  hiatus  which  this  involves. 

The  experimental  fact,  stated  in  one  way,  is  as  follows  :  We  take  a 
definite  quantity  of  an  element  A,  and  ascertain  the  quantity  of  an  ele- 
ment B  which  unites  with  it.  Then  we  measure  the  quantity  of  C  which 
unites  with  this  quantity  of  B  ;  then  that  of  D  which  unites  with  this 
amount  of  C,  and  so  forth.  We  thus  obtain  a  series  of  numerical  re- 
sults (equivalents)  such  that  each  quantity  in  the  series  is  that  which 
unites  with  the  neighbouring  quantities  of  adjacent  elements  on  each  side 
of  it.  Now  we  discover  that  the  stated  quantities  of  remoter  elements 
are  also  such  as  enter  into  combination,  either  as  they  stand  or  with  the 
use  of  the  principle  of  small  integral  multiples.  It  is  this  fact  which 
enables  us  to  assign  individual  combining  (atomic)  weights  to  the  ele- 
ments. Without  it,  chemical  proportions  would  be  a  waste  of  unrelated 
percentage  compositions,  and  our  much  cherished  formulae  and  equa- 
tions would  have  no  existence. 

The  matter  is  explained  with  exceptional  clearness  in  Young's  Ele- 
mentary Principles  of  Chemistry,  23-26,  and  242-243.  See  also 
Vaughan  Cornish,  Practical  Proofs  of  Chemical  Laws,  chapters  I.  and  IV. 


76       THE  INTRODUCTION  OF  THE  SUBJECT 

mands  that  some  particular  set  shall  be  preferred.  It  is  clear 
that  numbers  less  than  the  hydrogen  equivalents  will  be  in- 
convenient, as  they  must  either  make  hydrogen  itself  less 
than  unity  or  introduce  unnecessary  multiples  whenever  they 
are  used.  The  selected  combining  weights  (atomic  weights) 
may  be  given,  and  will  be  seen  to  be  frequently  small  mul- 
tiples of  the  hydrogen  equivalents.1  The  basis  of  selection 
cannot  be  further  explained  without  the  use  of  the  conse- 
quences of  Avogadro's  hypothesis. 

This  point  in  the  development  of  the  principles  forms  a 
convenient  halting  place,  and  we  shall  not  pursue  the  subject 
further  at  present.  The  results  of  the  work  we  have  outlined 
suffice,  if  the  teacher  so  desires,  to  enable  him  logically  to 
introduce  symbols  and  equations.  At  this  point,  or  a  little 
later,  if  he  sees  fit,  he  may  also  present  the  explanation  of  the 
last  three  generalizations  which  the  atomic  theory  furnishes. 
The  discussion  of  the  relations  of  symbols  (p.  7  7)  and  of  the 
atomic  theory  (p.  154)  to  introductory  work  will  be  taken  up  later. 

It  will  be  seen  that  the  chief  theoretical  subjects  affecting  the 
quantitative  description  of  chemical  change  which  still  re- 
Avogadro's  mam  fc>r  consideration  are  :  Avogadro's  hypothesis 
Hypothesis,  and  its  application  through  measurement  of  the 
density  of  gases  to  the  determination  of  molecular  weights,  the 
final  adjustment  of  combining  (atomic)  weights,  and  the  ex- 
planation of  valency.  It  might  be  noted  at  this  point  that 
many  teachers  do  not  favour  a  complete  discussion  of  these  subjects 
in  the  secondary  school.  They  are  undoubtedly  difficult,  and 
must  necessarily  occupy  a  great  deal  of  time,  and,  when  all  is 
said  and  done,  the  pupils  are  little  likely  long  to  retain  much  of 
the  intricate  reasoning  which  is  inseparable  from  their  discussion. 
It  is  true  that,  like  any  other  part  of  the  science,  the  study  of 
this  aspect  of  it  must  furnish  admirable  discipline,  but  it  is  a 


1  Throughout,  oxygen  equivalents  (O  —  8  and  II  =  1.0076)  may  be 
used  just  as  easily  as  hydrogen  equivalents  (H  =  i  and  O  =  7.94),  and 
they  have  the  advantage  of  leading  directly  to  the  standard  atomic 
weights  (O  =  16.00). 


THE  INTRODUCTION  OF   THE  SUBJECT       77 

question  whether  even  in  this  point  of  view  a  more  economical 
use  of  the  time  may  not  be  made  by  substituting  other  and 
simpler  chemical  topics.  These  particular  things  are  not 
likely  to  find  application  in  every-day  life,  even  if  they  are 
retained,  and,  in  the  less  usual  case  of  the  pupil  who  afterwards 
attends  a  university  or  technical  school,  this  subject  will  in 
any  case  have  to  be  dealt  with  afresh.  It  is  on  account  of 
these  facts  that  I  am  inclined  to  justify  the  less  rigid  treatment 
of  the  matter  of  combining  weights,  in  order  that  apart  from 
Avogadro's  hypothesis  we  may  have  a  reasonable  basis  for  the 
use  of  equations. 

V.     The  Relation  of  the  Quantitative  Laws  to  Formulae  and 
Equations. 

One  of  the  chief  criticisms  of  the  teaching  of  chemistry  at 
the  present  day  is  that  much  of  it  fails  to  make  clear  the  place 
of  the  balance  in  chemical  work  and  the  relation  of  the  results 
of  measurement  to  the  plan  chemists  have  adopted  of  expressing 
these  results,  namely,  by  the  use  of  the  combining  or  atomic 
weight  as  the  unit  of  quantity  for  each  element.  I  am  not,  for 
the  moment,  referring  to  the  much  debated  question  whether 
the  pupils  can  or  should  do  quantitative  work.  It  is  the  un- 
assailably  fundamental  character  of  the  quantitative  data  and 
their  interpretation  that  I  would  emphasize.  It  is  this  that  has 
made  chemistry  an  exact  science.  Thus,  even  if  he  has  no 
balance  at  all,  or  no  inclination  to  use  it,  the  teacher  is  still 
compelled  to  reach  the  core  of  the  science,  if  he  reaches  it  at 
all,  by  explaining,  in  one  or  two  actions  at  least,  how  one  could 
set  about  measuring  the  quantities  concerned. 

When  the  time  comes  for  expressing  these  measurements  in 
the  form  of  symbols  and  equations  the  pupil  must  be  shown 

clearly  how  the  translation  into  the  conventional 

,        .     ,     -          ,  rr         ,  Expression  of 

chemical   formulae  is   effected,  i    It   may   seem   to  Quantitiesby 

some  readers  a  strange  statement  to  make,  but  I   Formulae- 
believe  that  many  will  bear  me  out,  when  I  say,  that,  although 
the  modern  works  have  included  the  stage  of  measurement, 


78       THE  INTRODUCTION  OF  THE  SUBJECT 

there  are  few  elementary  text-books  in  which  any  attempt  is 
made  to  furnish  the  links  between  experiment  and  equation.  I 
know  hardly  any  that  I  could  put  into  the  hands  of  an  intelligent 
person  for  study,  with  the  least  confidence  that  this  connection 
would  be  understood.1  It  is  to  be  feared  that  the  number  of 
teachers  who  furnish  this  link  must  be  limited,  for  the  books 
must  by  all  means  represent  the  average,  if  not  the  best  teach- 
ing in  the  country. 

A  concrete  illustration  will  make  most  clear  what  is  meant. 
Suppose  the  teacher  deems  that  the  time  has  come  for  the 
An  use  of  formulae  and  equations  to  begin,  and  that 

Illustration.  tne  introduction  has  been  conceived  somewhat  in 
the  spirit  of  the  preceding  section.  To  be  specific,  suppose 
that  he  decides  to  do  this  in  connection  with  the  study  of 
oxygen.  Let  us  further  suppose  that  sulphur  is  the  first  body 
whose  union  with  oxygen  is  observed.  After  qualitative  obser- 
vation the  question  of  quantity  arises.  It  is  necessary  to  ascer- 
tain, or  assume  as  known,  the  weights  of  two  of  the  three  bodies, 
sulphur,  oxygen,  and  sulphur  dioxide.  The  third  can  then  be  in- 
ferred. The  simplest  experimental  method  is  that  which  weighs 
the  sulphur  and  burns  it  in  excess  of  oxygen,  and  catches  and 
weighs  the  sulphur  dioxide.  The  apparatus  and  general  pro- 
cedure must  be  sketched  and  described  or  shown.2  The  result 


1  The  explanation  is  admirable  in  Reynolds,  ibid.,  69-72  ;  it  is  clear,  but 
too  long  postponed  in  Torrey,  ibid.,  315-316  ;  in  Young,  ibid.,  75-76,  it  is 
satisfactory. 

2  Newth,  Elementary  Inorganic  Chemistry  (Longmans,  Green  &  Co.), 
p.  108,  describes  this  experiment.  It  will  do  very  well  for  description, 
but  I  do  not  advise  its  performance,  as  it  requires  careful  watching,  and 
I  have  found  that  the  boat,  or  glass  of  the  tube,  often  acts  catalytically 
and  sulphur  trioxide  is  formed  in  such  quantities  that  the  weight  of  the 
sulphur  dioxide,  and  therefore  of  the  oxygen,  comes  out  much  too 
large. 

Perhaps  the  best  experiment  for  illustrating  the  making  of  a  formula 
is  the  solution  of  a  weighed  piece  of  iron  wire  in  nitric  acid,  and  the 
evaporation  and  ignition  of  the  residue  (Fe2O8).  The  indirect  nature 
of  the  oxidation  is  unfortunate.  But  the  oxides  which  are  formed  easily 
by  direct  union,  like  those  of  copper  and  magnesium,  do  not  afford  an 
example  of  the  use  of  multiples  of  the  combining  weights,  while  there 


THE  INTRODUCTION  OF  THE   SUBJECT       79 

of  the  experiment  leads  to  the  conclusion  that  the  proportion 
by  weight  of  sulphur  to  oxygen  is  50  :  50  in  a  hundred  parts,  or 
i  :  i,  almost  exactly. 

Now  chemists  express  this  result  in  a  system  in  which  the 
combining  (atomic)  weight  of  each  element  is  the  unit.  There- 
fore, what  we  desire  next  is  to  know  the  value  of  x,  the  number 
of  combining  weights  of  sulphur,  and  y,  the  number  of  com- 
bining weights  of  oxygen  in  the  equation  : 

x  X  comb.  wt.  of  sulph.  :  y  X  comb.  wt.  of  oxygen  —  i  :   i. 

The  combining  weights  must  be  known  or  the  operation  stops 
here,  and  the  equation  cannot  be  reached  until  they  are  known. 
We  state  them  to  be  32  and  16  respectively.  The  problem 
then  is  to  find  the  simplest  values  of  x  and  y  in  the  equation 
.%•  X  32  :  _y  X  16  —  i  :  i.  If  the  combining  weights  have-been 
successfully  chosen,  x  and  y  must  be  rational  numbers,  and 
will  usually  be  small  numbers.  This  is  the  property  of  chemical 
combination  mentioned  in  last  section  (p.  75),  in  consequence 
of  which  alone  we  possess  interchangeable  combining  weights  of 
any  kind  at  all.  Here  evidently  x  :  y  =  i  :  2.  Now  the  sym- 
bol S  expresses  32  parts  of  sulphur,1  the  combining  weight,  and 


are  objections  on  the  score  of  experimental  difficulty  to  the  use  of  the 
oxides  of  carbon  and  phosphorus. 

1  This  statement  of  the  meaning  of  the  equation  harmonizes  with  the 
mode  of  approach  from  the  experimental  side  which  we  have  pursued. 
In  this  point  of  view,  S  may  not  be  used  as  a  contraction  for  the  name  of 
the  body.  Nor  does  it  mean  an  atom  of  sulphur,  since  atoms  are  not 
perceived  in  experiment. 

The  symbol  represents,  not  the  yellow,  light  solid  which  is  indicated 
by  the  word  sulphur,  but  the  part  of  the  mass  of  the  compound  (in  this 
case,  sulphur  dioxide)  which  was  originally  sulphur,  but  now  shows  none 
of  its  properties.  Some  chemists  distinguish  between  the  free  body,  or 
"simple  "  (as  opposed  to  compound),  and  the  element.  The  latter  is  the 
same  material  in  its  combined  and  unrecognizable  form.  The  atomic 
theory,  in  explaining  the  quantitative  laws  of  combination  by  supposing 
each  constituent  to  be  done  up  in  little  pieces  of  uniform  weight,  inci- 
dentally leads  us  to  suppose  also  that  the  pieces  remain  intact  after 
combination,  It  suggests  that  the  pieces  are  stuck  together  without 
losing  their  individuality.  So  the  symbol  SO2  shows  them  to  us  side 
by  side.  But  precisely  because  the  theory  and  the  atomic  ideas  con- 


80       THE  INTRODUCTION  OF   THE  SUBJECT 

the  symbol  O  stands  for  16  parts  of  oxygen,  its  combining  weight. 
Therefore  the  composition  of  sulphur  dioxide,  in  terms  of  the 
chemical  units  of  quantity  is  i  X  S :  2  X  O,  which  is  equivalent 
arithmetically  to  the  proportion  by  weight,  i  :  i,  found  in  the 
experiment.  The  formula  is  thus  SO2-  Since  one  combining 
weight  of  sulphur  and  two  of  oxygen  are  required  to  form  this, 
the  equation  is  S  +  O2  =  SC^.1 

Every  step  in  this  process  is  easily  followed,  and  the  equation 
is  seen  to  rest  directly  on  experiment,  as  it  should  do  in  a  science 
which  claims  to  be  experimental.  The  only  point  of  possible 
obscurity  is  in  the  justification  of  the  atomic  weights.  If  Avo- 
gadro's  hypothesis  has  not  been  given,  that  difficulty  cannot  be 
fully  met.  The  pupil  has  seen,  however,  how  a  set  of  combin- 
ing weights  can  be  established,  and  may,  without  confusion,  be 
asked  to  leave  in  suspense  the  question  of  why  these  particular 
values  (such  as  32  for  sulphur  rather  than  32/2  or  32/5)  have 
been  finally  chosen.  This  whole  proceeding  must  be  repeated 
with  each  succeeding  equation  for  some  little  time,  until  it  is 
thoroughly  familiar.  If  the  teacher  can  actually  perform  one 


nected  with  the  formula  prejudice  us  in  favour  of  the  view  that  the  sul- 
phur persists  in  the  compound  in  this  way,  we  are  apt  to  forget  that 
the  theory  makes  no  attempt  to  explain  why  the  product  is  a  wholly 
new  species  of  matter.  It  simply  ignores  the  fact  that  a  body  with  a 
powerful  odour  and  the  other  familiar  physical  and  chemical  properties 
of  sulphur  dioxide  has  appeared,  and  that  the  characteristic  properties  of 
the  two  bodies  from  which  it  was  made  have  been  submerged  (cf.  Per- 
kin  and  Lean,  ibid.,  322).  In  other  words,  we  are  put  in  the  risky 
position  of  trying  to  think  that  the  bodies  are  both  still  there  and  both 
gone  at  the  same  time.  The  qualitative  facts  are  better  explained  by 
supposing  complete  change  of  the  sulphur  and  oxygen  and  production  of 
the  compound  out  of  the  material  (cf.  pp.  156,  158).  Thus,  in  the  formula 
of  the  compound  SO2,  at  least,  the  material  denoted  by  S  is  not  free 
sulphur  (the  "  simple  "),  and  the  symbol  and  word  are  not  interchange- 
able,—  at  all  events,  not  until  the  atomic  theory  has  been  given,  and, 
strictly  speaking,  not  even  then. 

1  The  general  solution  of  this  problem  consists  in  taking  the  weights 
of  the  constituents  found  in  any  sample  of  a  compound,  dividing  each 
such  weight  by  the  combining  weight  of  the  corresponding  element, 
and  finding  the  whole  numbers  which  stand  in  the  same  ratio  as  the 
quotients. 


THE  INTRODUCTION  OF  THE  SUBJECT       8 1 

experiment  before  the  class,  the  impression  will  be  incomparably 
more  definite  and  lasting.  If  it  is  possible  to  include  such  an 
experiment  in  the  laboratory  work  of  the  pupils,  the  effect  will  be 
still  better.  But  my  point  is  that  the  equation  can  never  be 
understood  unless  the  quantitative  measurement,  whether  by 
description,  demonstration,  or  individual  performance  makes 
relatively  little  difference,  is  brought  to  the  notice  of  the  pupil, 
its  numerical  result  seen,  and  its  translation  into  the  form  of  an 
equation  exhibited.  Without  some  such  explanation,  the  equa- 
tion is  bound  to  be  a  mysterious  thing,  and  must  remain  utterly 
unconnected  by  any  visible  link  with  the  chemistry  of  the  lecture- 
table  and  the  laboratory. 

It  will  be  seen  that  we  have  treated  the  symbol  and  the  equa- 
tion as  if  they  represented  the  materials,  not  by  atoms  and  mol- 
ecules but  by  weight.      It  is  frequently  assumed 
that  the  reverse  of  this  is  the  correct  view.    Yet  the   ^Represent 
fact  is  that  the  equation  is  seldom  used  in  the  lat-   Weights,  not 
ter  sense,  and  there  is  no  impropriety  in  treating  the 
former    as  its    primary   signification.     Chemistry   is    primarily 
experimental.1     To   illustrate.      Marshall    (JouR.  CHEM.  Soc., 
Lond.  LIX.,  771)  found  a  white  crystalline  body  in  a  cell, 
originally  filled  with  a  solution  of  potassium  bisulphate,  through 
which  a  current  of  electricity  had  been  flowing  for  a  long  time. 


\ 


1  The  equation  may  therefore  be  used  solely  as  a  record  of  quantita- 
tive data  until  the  atomic  theory  has  been  introduced.  After  that  has 
occurred,  the  explanation  that  the  chemical  unit  quantities  of  each  ele- 
ment are  likened  in  this  theory  to  atoms  will  naturally  be  given.  When 
Avogadro's  hypothesis  has  finally  defined  the  chemical  molecule,  the 
equation  comes  up  once  more.  This  time  it  has  to  be  changed  to  cor- 
respond with  the  new  ideas,  if  the  items  it  contains  are  to  be  complete 
molecules,  and  the  equation  is  to  represent  the  change  as  if  it  took  place 
in  the  physical  minimum  of  materials.  Where  we  can  measure  the  molec- 
ular weights,  —  as  in  the  case  of  volatile  substances,  —  the  formulae  will 
now  be  adjusted  so  as  to  represent  molecules  (as  O2-f2H2— »2H2O)  and 
the  equation  will  embody  the  change  in  petto  physically,  as  well  as  in  pro- 
portions by  weight  chemically.  For  practical  purposes  this  form  of 
equation  is  preferable  only  when  gases  are  concerned.  With  bodies 
which,  under  ordinary  conditions,  are  not  gases  (as  P4),  it  is  a  needless 
complication. 

6 


82       THE  INTRODUCTION  OF  THE  SUBJECT 

He  did  not  for  a  moment  attempt  to  ascertain  the  nature  of  the 
body,  and  the  action  by  which  it  had  been  formed,  by  trying  to 
see  how  the  molecules  of  the  bisulphate  were  affected  by  the 
current  and  what  atoms  were  contained  in  the  molecules  of  the 
new  substance.  If  the  chemist  did  not  think  in  a  more  con- 
crete way  in  his  work  than  he  seems  often  to  do  in  his  teaching, 
his  mind  would  be  so  befogged  with  theory  that  he  would  never 
accomplish  anything.  Marshall  simply  analysed  the  body, 
found  that  the  elements  potassium,  sulphur,  and  oxygen  were 
present  in  it,  and  determined  the  percentage  of  each.  A 
process  of  reasoning  essentially  the  same  as  that  in  our  illustra- 
tion gave  the  formula  KSO4.  Comparison  with  the  bisulphate 
(KHSO4)  showed  that  hydrogen  had  been  eliminated,  and,  as 
this  gas  was  liberated  during  the  electrolysis,  the  simplest  equa- 
tion was  evidently  :  KHSO4=KSO4+H.  This  was  the  first  iso- 
lation of  a  persulphate.1 

Naturally  only  a  mere  fraction  of  the  actions  studied  in  an 
elementary  course  can  be  treated  quantitatively.  But  when, 
without  exact  measurement  other  equations  are  constructed  by 
the  help  of  such  data  as  the  pupil's  experiments  afford,  or  are 
even  taken  from  the  book,  the  learner  will  still  realize  that  the 
process  described  above  was  carried  out  by  some  one,  and  the 
origin  and  meaning  of  the  equation,  once  grasped,  will  never 
again  become  obscure. 

'Equation  writing,'  in  the  sense  in  which  the  phrase  is  com- 
monly used,  will  be  a  necessary  exercise  in  connection  with 
Equation  tne  making  of  the  record  of  each  experiment  in  the 
Writing.  note-book,  but,  after  rational  explanation  like  the 
above,  it  will  be  largely  a  genuine  exercise  in  chemical  thought, 
based  on  inferences  from  observation.  Without  any  such  ex- 
planation, it  is  likely  to  be  a  combination  of  copying  and  illogi- 


1  Subsequent  study  showed  that  persulphuric  acid  was  a  dibasic 
acid,  and  that  therefore  the  formula  of  the  salt  was  K2S2O8.  The  above 
process  could  not  go  beyond  correctly  expressing  the  proportions  by 
weight  in  terms  of  multiples  of  the  atomic  weights.  Entirely  different 
means  were  required  to  furnish  this  improvement. 


THE  INTRODUCTION  OF  THE  SUBJECT       83 

cal  collocation  of  letters,  accompanied  by  vague  gropings  after 
some  rule.  If  '  rules  '  are  supplied,  then  the  last  chance  of  any 
chemical  benefit  surviving  is  removed  and  some  puzzle  like  the 
once  popular  "  fifteen  puzzle  "  would  furnish  more  exercise  for 
the  intelligence  and  just  as  much  chemistry. 

If  the  exercise  is  merely  arithmetical  like  this : 

"  Complete  the  following  : 

CaCO3-CO2=? 
2  KNO2  =  N2O3  +  ? 
Pb  +  HN03  =  Pb  (N03)2  +  H20  +  NO," 

a  little  of  it  may  be  safe  and  useful.  Even  students  in  universi- 
ties can  seldom  count  the  numbers  of  atomic  weights  of  each 
element  correctly.  But  too  much  of  this  sort  of  thing  suggests 
to  the  pupil  that  a  chemical  change  can  be  predicted  safely  from 
manipulation  of  the  formulae  of  the  factors  entering  into  it,  and 
withdraws  the  attention  from  careful  reasoning  from  observation. 

This  is  especially  likely  when,  as  in  the  book  from  which  the 
above  is  taken,  a  large  number  of  such  truncated  equations  are 
given  early  in  the  course,  before  the  actions  with  which  they 
deal  have  been  studied.  We  are  not  surprised  a  few  pages 
further  on  to  read :  "  HC1  is  the  formula  of  an  acid  because 
it 1  consists  of  hydrogen  united  with  a  non-metallic  element," 
followed  by  an  exercise  in  selecting  "  from  these  symbols  " 
"  the  ones  which  stand  for  acids  :  "  "  H2C2O4,  CaCO3,  NaOH, 
H2S."  The  reasons  for  the  decision  are  to  be  given.  How 
unpleasant  it  would  have  been  if  the  printer's  devil  had  mali- 
ciously added  H6C2O,  H3NO,  and  P(OH)3  to  the  list ! 

In  view  of  the  fact  that  equations,  symbols,  formulae,  etc.,  are 
not  parts  of  chemistry,  but  of  our  mode  of  recording  The  Tlmc  for 
chemical  facts,  it  seems  desirable  to  plant  the  facts   introducing 
and  their  importance  securely  in  the  mind  of  the  Eauations< 
pupil  before  these  conventions  are  considered.     When  they  are 

1  This  reminds,  one  irresistibly  of  a  pupil's  answer  quoted  by  Tilden : 
"Metals  differ  from  non-metals,  both  by  ending  in  um  and  having  a 
metallic  lustre." 


84        THE  INTRODUCTION  OF  THE  SUBJECT 

given  they  should  be  clearly  distinguished  from  the  facts  of  the 
science  and  explained  as  a  kind  of  abbreviated  language  for 
expressing  the  facts. 

Since  they  are  quantitative  expressions,  they  cannot  logically 
appear  before  the  method  of  measurement  has  been  explained. 
If  the  problem  were  that  of  explaining  to  a  visitor  from  Mars 
the  system  of  money  and  exchange  used  on  this  planet,  we 
should  not  first  invite  him  to  memorize  part  of  the  stock  ex- 
change and  commercial  reports  of  a  newspaper.  He  would 
have  to  become  familiar  with  the  materials  themselves,  and 
understand  the  object  and  machinery  of  exchange,  before  he 
could  intelligently  handle  the  conventions  by  which  we  have 
come  to  chronicle  them.  The  introduction  of  equations  soon 
after  the  quantitative  laws  have  been  explained  and  illustrated 
is  desirable,  because  their  use  gives  much  greater  precision  to 
the  pupil's  conception  of  each  chemical  change.  On  account 
of  the  abuse  to  which  they  are  subject,  their  postponement  to  a 
very  late  stage,  or  even  omission  altogether,  has  been  seriously 
advised  by  many  teachers.  This,  however,  is  surely  an  extreme 
view.  Why  propose  excision  of  a  valuable  organ  when  the  cure 
of  the  disease  lies  in  the  hands  of  the  teacher  ? 


CHAPTER   IV 

INSTRUCTION   IN   THE   LABORATORY 

WE  have  already,  either  by  implication  or  directly,  touched 
upon  many  of  the  important  aspects  of  instruction  in  the  labora- 
tory. This  was  unavoidable,  since  the  purposes  and  results  of 
chemical  instruction  are  so  closely  bound  up  with  the  practical 
side.  We  must  now  discuss  the  subject  in  a  more  systematic 
manner.  The  value  of  laboratory  work  offers  a  convenient  title 
under  which  we  may  endeavour,  through  the  discussion  of  the 
benefits  it  may  confer,  to  set  forth  the  considerations  which 
affect  the  attitude  of  the  teacher,  and  are  to  be  used  in  mould- 
ing that  of  the  learner,  towards  the  science.  We  may" then  con- 
sider in  succession,  the  laboratory  directions,  the  attitude  of 
discoverer  or  verifier  which  the  pupil  may  be  induced  to  adopt, 
the  importance  of  technique,  the  question  of  quantitative  ex- 
periments, and  the  note-book. 

In  all  this,  of  course,  we  assume  that  the  teacher  is  provided 
with  a  laboratory  of  some  kind,  and  with  equipment  more  or 
less  adequate.  The  construction  and  furnishing  of  a  laboratory 
will  be  dealt  with  in  a  chapter  by  itself.  The  importance  of  its 
right  employment  in  teaching  chemistry  will  not  require 
separate  treatment,  since  it  will  emerge  very  distinctly  from 
the  results  of  our  discussion  of  the  topics  immediately  following. 

The  laboratories,  in  many  cases  magnificent,  with  which  new 
school  buildings  are  nowadays  usually  provided,  show  that  the 
necessity  for  having  them  has  been  recognised,  at  LatonAmy 
least  by  the  architects.     One  would  fain  think  that  Instruction 
their  importance  is  equally  appreciated  by  superin- 
tendents and  principals.     The  statement  made  by  the  Com- 
mittee of  Nine,  however,  although  startling  to  those  who  have 


86          INSTRUCTION  IN  THE  LABORATORY 

looked  into  one  or  two  of  the  best  schools,  and  have  not  taken 
the  average  of  the  secondary  schools  of  a  whole  state  into  con- 
sideration, is,  it  may  be  feared,  not  without  justification.  They 
say : l  "  While  the  laboratory  method  is  almost  universally  ap- 
proved by  the  science  teachers,  the  text-book  method  prevails 
in  the  schools,  to  such  an  extent  that  laboratory  work  is  inci- 
dental, inefficient,  and  in  many  cases  excluded  altogether." 
In  their  preliminary  report,  which  deals  with  this  phase  of  the 
subject  more  fully,  they  say : 2  "  It  is  true  that  attempts  at  labora- 
tory work  in  one  or  two  subjects  are  reported  by  the  schools  of 
the  State  of  New  York  almost  without  exception,  but  the  com- 
plaint is  made  that  the  laboratory  study  must  be  limited,  desul- 
tory, and  subordinate  to  the  study  of  books  with  classroom 
exhibitions."  They  attribute  this  condition  in  part  to  lack  of 
recognition  of  "  the  great  labour  involved  in  the  conduct  of  good 
laboratory  work,"  and  the  fact  that  "  the  reputation  of  the 
teacher  and  the  standing  and  financial  support  of  the  school 
are  affected  by  the  results  of  examinations,"  while  "the  results 
of  laboratory  study  cannot  be  tested  by  the  current  methods  of 
examination."  As  this  committee  included  representatives  from 
the  high  schools,  as  well  as  the  normal  schools  and  colleges  of 
New  York  State,  and  as  this  opinion  was  expressed  after  pro- 
longed and  minute  study  of  the  actual  condition  in  the  schools 
of  a  state  which  is  certainly  not  below  the  average  education- 
ally, it  must  be  regarded  as  a  serious  criticism  of  the  present 
teaching  in  the  whole  country.  Only  the  constant  efforts  of  the 
teachers  of  science,  to  awaken  the  minds  of  other  school  offi- 
cers and  of  the  public  at  large  to  the  indispensability  of  reason- 
able expenditures  for  scientific  equipments,  and  reasonable 
consideration  of  the  points  made  by  the  committee,  can  secure 
the  gradual  remedy  of  this  state  of  affairs.  No  special  benefit 
is  to  be  expected  from  the  teaching  of  science  until  a  far-reach- 
ing change  has  been  brought  about. 


1  University  of  the  State  of  New  York,  High  School  Bulletin  No.  7, 
706. 

2  JOURNAL  OF  PEDAGOGY,  Vol.  XL  (1898),  119. 


INSTRUCTION  IN  THE  LABORATORY         87 

I.     The  Value  of  Laboratory  Work  for  General  Education. 

a.  For  Teaching  Knowledge-making  by  Observation  and  In- 
duction:—  Observation  in  chemistry  implies  something  much 
more  complex  and  difficult  than  we  sometimes  ap-  Wnatisim_ 
preciate.     In  its  simplest  terms  it  may  consist  in  plied  in 
noticing  the  colour    of  a    precipitate,   or   stating  Observati011- 
whether  bubbles  of  gas  do  or  do  not  appear,  or  perhaps  in 
describing   the   form  of  a  crystal.     This   demands  what   one 
writer  has  described   as  "  ocular   accuracy."     The   process  is 
one  of  the  mind,  although  the  phrase  suggests  that  the  eye  as 
a  physical  instrument  is  mainly  concerned.     In  many  experi- 
ments, however,  the  use  of  experience  and  reasoning  in  obser- 
vation so  greatly  predominates,  that  the  part  which  the  eye  or 
the   sense   of  touch  plays   becomes   relatively  inconspicuous. 
We  read  of  observation   consisting   in   the  "  training   of  the 
senses."     The   phrase   is  vague.     It  should   be   remembered 
that  the  reactions  of  our  sense  organs  are  scarcely  affected  by 
practice.     Galton  has  shown  that  sailors'  eyes,  instead  of  being 
more  efficient  physically  than  other  peoples',  are  really  less  sen- 
sitive than  the  average.     It  is  the  ability  of  the  seaman   to 
interpret  what  he  sees  in  the  light  of  experience  that  makes 
him  a  better  observer  of  some  things  than  the  landsman.    A  boy 
may  see  ten  times  as  much  as  a  man,  yet  the  man  will  learn  ten 
times  more  from  what  he  sees  than  the  boy.     Applying  this  to 
the  matter  in  hand,  we  see  that  the  training  of  a  pupil  in  obser- 
vation consists  really  in  storing  his  mind  with  suitable  experi- 
ence, all  thoroughly  classified  and  digested.     Ability  to  observe 
chemical  phenomena  is  an  attribute  of  the  chemist,  and  teach- 
ing observation  consists  really  in  teaching  chemistry. 

b.  For  Teaching  Knowledge-making  by  the  Study  of  Natural 
Objects  and  Phenomena:  —  As  we  have  seen  (pp.  10  and  49), 
training  in  observation  in  the  fullest  sense  of  the  practical 
term  may  be  obtained  from  the  study  of  languages  JJ^ato 
and  other  book  work.     The   man  who  is  trained,   Experience, 
however,  in  this  direction  only,  may  remain  bookish  and  un- 


88          INSTRUCTION  IN  THE  LABORATORY 

practical.  The  knowledge  by  which  we  live  is  not  furnished  with 
an  index,  nor  is  it  arranged  alphabetically.  It  is  thrown  at  us 
much  like  the  experience  of  the  chemist,  and,  as  a  school  of  edu- 
cation and  a  sphere  of  activity,  the  world  is  more  like  a  labora- 
tory than  a  library.  The  experience  in  chemistry  quickly  shows 
the  fallacies  into  which  we  continually  fall,  and  from  which  ex- 
periment and  renewed  observation  alone  can  rescue  us.  We 
quickly  learn  that  the  operation  of  thinking  clearly  and  keeping 
our  ideas  in  touch  with  facts  is  not  a  natural  attribute  of  the 
untrained  mind.  In  studying  chemistry  in  the  laboratory  we 
acquire  the  habit  of  applying  to  concrete  things  the  methods 
of  observation,  of  induction,  and  of  testing  every  hypothesis  by 
reference  to  facts,  which  are  indispensable  to  clear  thought 
about  such  matters.  The  application  of  the  method  is  a 
quality  of  the  scientific  mind,  whether  that  mind  is  employed 
in  business  or  in  study.  As  Professor  Remsen  l  says :  "  By 
a  scientific  mind  is  meant  one  that  tends  to  deal  with  questions 
objectively,  to  judge  things  on  their  merits,  and  that  does  not 
tend  to  prejudge  every  question  by  the  aid  of  ideas  formed 
independently  of  the  things  themselves. 

To  illustrate : 2  When   ammonium   chloride   is   heated  in  a 
test-tube  and  litmus  paper  shows  the  presence  of  ammonia  at 

illustration  t^ie  moutn  °^  tne  tu^e>  ^e  student  instantly  says 
of  Faulty  that  ammonia  has  been  given  off,  and  thinks  of 
uc  on.  ^  remammg  solid  as  containing  the  hydrogen 
chloride.  Presently  the  test  paper  shows  the  arrival  of  this 
acid,  and  he  is  reminded  that  the  other  product  is  a  gas. 
If  he  is  now  asked  why  the  ammonia  appeared  first,  he  will 
invariably  say  that  it  must  have  been  formed  before  the 
hydrogen  chloride !  It  usually  comes  as  a  surprise  when  you 
lead  him  to  see  that  in  the  decomposition  of  a  substance 

1  Address  on  "  The  Chemical  Laboratory,"  delivered  in  connection 
with  the  opening  of  the  Kent  Chemical  Laboratory  of  the  University  of 
Chicago.     NATURE,  XLIX.  (1894),  531. 

2  An  excellent  discussion  of  this,  with  many  historical  illustrations,  is 
given  by  Tilden,  Hints  on  the  Teaching  of  Elementary  Chemistry.     Lon- 
don and  New  York,  Longmans,  Green  &  Co.     1895.     PP-  I-I1* 


INSTRUCTION  IN  THE  LABORATORY         89 

into  two  gaseous  molecules,  the  products  cannot  be  formed 
otherwise  than  simultaneously.  The  same  pupil  would  not 
have  made  so  grotesque  a  mistake  in  reasoning  in  geometry  or 
in  translation  from  French.  It  is  the  reasoning  about  material 
objects  and  phenomena  which  is  difficult  to  him  because  it  is 
unfamiliar. 

c.  For  Teaching  Caution  and  Mental  Rectitude : — The  illustra- 
tion just  given  points  further  to  the  continual  discipline  which 
the  pupil  must  receive  in  the  necessity  for  caution  Heed  of  Care 

in  forming  conclusions.     No  work  so  much  as  that  in  Drawing 
...  .  ,     .,  r        Conclusions, 

in  chemistry  impresses  one  with  the  necessity  for 

distrusting  preconceived  notions,  or  furnishes  a  better  prepara- 
tion for  tenaciously  employing  this  principle  as  one  of  the  best 
guides  in  all  the  actions  of  life.  The  line  between  the  mini- 
mum inference  which  the  facts  actually  justify,  and  the  more 
extensive  one  which  we  are  continually  tempted  to  draw,  is 
often  so  easily  passed  that  the  most  varied  experience  in  search- 
ing for  it  and  remaining  on  the  safe  side  can  never  make  the 
process  too  familiar.  Take,  for  example,  the  case  of  the  Bun- 
sen  burner.  When  the  pupil,  after  he  has  observed  the  dif- 
ference which  the  position  of  the  ring  at  the  bottom  of  the 
burner  makes,  is  asked  what  the  openings  have  to  do  with  the 
matter,  he  will  invariably  say  that  it  is  the  admission  of  oxygen 
which  causes  this  difference.  This  statement  may  even  be 
found  in  many  books,  in  spite  of  the  fact  that  nitrogen  and  other 
gases  which  contain  no  oxygen  have  the  same  effect.1  The 
higher  temperature  of  the  Bunsen  flame  is  sufficiently  explained 
by  its  smaller  size.  The  liberation  of  free  carbon  in  luminous 
flames  is  another  rock  of  offence.  It  seemed  to  be  accounted 
for  by  the  theory  that  the  hydrogen  of  the  hydrocarbons  burned 
more  easily,  until  this  was  shown  conclusively  to  be  the  exact 
contrary  of  the  fact  by  Smithells.2 

The  custom  of  careful  scrutiny  of  hypotheses  and  their  con- 


1  See  Newth's,  Inorganic  Chemistry.     London  and  New  York,  Long- 
mans, Green  &  Co.  1894.     Pp.  291-306,  particularly  304. 

2  NATURE,  XLIV  (1893),  86.     For  further  references,  see  p.  215. 


90          INSTRUCTION  IN   THE  LABORATORY 

tinual  probation  before  the  court  of  experiment  begets  a  habit  of 
mind  which  finally  finds  delight  in  the  search  for  exact  knowledge 
and  correct  opinions  for  their  own  sake.  In  these  days  of  ex- 
aggeration and  superficiality  the  influence  of  the  tendency  of 
laboratory  work  to  the  fostering  of  mental  rectitude  cannot  be 
prized  too  highly. 

d.  Other  Benefits  of  a  General  Nature : —  Laboratory  work  is 
undoubtedly  of  value  in  that  cultivation  of  the  mind  which  is 
expressed  by  care  and  neatness  in  mechanical  matters,  and  in 
dexterity  in  the  manipulation  of  materials.  This  training  has 
undoubtedly  a  broader  significance,  beyond  the  operations 
and  objects  peculiar  to  chemical  work.  Perhaps,  as  a  substitute 
for,  or  supplement  to  manual  training,1  it  may  be  said  to  have 
some  value  in  a  partial  way. 

In  all  instruction  the  personality  of  the  teacher  is  held  to  be  a 
factor  of  not  less  importance  than  the  nature  of  the  subject 
taught.  The  close  personal  contact  which  laboratory  instruction 
secures  between  the  pupil  and  teacher,  and  the  consequent 
greater  opportunity  which  his  personality  has  to  impress  itself 
upon  the  pupils,  is  not  one  of  the  least  of  the  benefits  we  are 
discussing.  There  are  others  that  might  be  mentioned;  several, 
such  as  the  liberation  from  the  bondage  of  authority  (pp.  10 
and  51),  have  already  been  discussed  in  other  connections. 
The  examples  we  have  given  (in  b  and  c  above),  if  carefully 
thought  out,  will  furnish  a  clearer  insight  into  the  value  of 
laboratory  work  than  any  mere  enumeration  of  ours  could  do. 

II.     Value  of  Laboratory  Work  for  Instruction  in  Chemistry. 

a.  For  giving  First-hand  Knowledge :  •«—  The  study  of  chemis- 
try, or  any  other  body  of  knowledge,  must  be  carried  out  by 
direct  encounter  with  the  material  of  the  science  itself.  The 
study  of  what  some  one  else  has  said  or  thought  about  the  sub- 
ject is  an  interesting,  but  entirely  different  exercise.  We  do 
not  study  Latin  by  reading  an  English  translation,  or  an  essay 

1  W.  E.  Bennett,  Manual  Training  of  Chemistry.  University  of  the 
State  of  New  York,  High  School  Bulletin  No.  13,  926. 


INSTRUCTION  IN  THE  LABORATORY         91 

on  the  author's  work.  Every  one  understands  that  the  study 
of  Latin  means  the  study  of  the  text  itself.  So  the  term  "  study 
of  chemistry  "  can  be  properly  applied  to  nothing  but  laboratory 
study  of  the  subject.  An  author's  explanations  and  verbal 
statements  are  but  a  feeble  and  exceedingly  partial  substitute 
for  the  facts  themselves.  Really  to  know  what  the  facts  of 
chemistry  are,  they  must  be  seen  and  handled  directly.  The 
books  are  not  chemistry,  but  literature,  and,  as  some  one  has 
said,  they  are  mostly  poor  literature  at  that. 
j^In  order  that  there  may  be  no  question  of  the  pre-eminence 
of  practical  experience,  the  course  should  be  arranged  round 
the  laboratory  work,  and  the  latter  should  carry  the  Tne  study 

thread  of  the  subject.      Classroom  work  and  other  arranged 

round  the 
exercises  should  be  adjusted  to  this  and  used  as  Laboratory 

supplements.  This  of  course  presupposes  the  Work' 
existence  of  certain  qualities  in  the  chosen  laboratory  outline 
which  shall  fit  it  f6r  furnishing  the  backbone  and  carrying  the 
burden  of  the  workj  It  is  evident  that  if  the  relation  of  the 
other  parts  to  the  laboratory  work  is  not  that  which  we  have 
suggested,  if,  for  example,  the  recitations  from  a  text-book  form 
the  only  continuous  and  logical  feature  of  the  course,  the  atti- 
tude of  the  student  towards  the  laboratory  work  will  be  entirely 
false.  If  the  text-book  is  taken  as  the  basis,  and  the  impression 
is  given  that  experiments  are  thrown  in  like  the  engravings  and 
autograph  letters  in  what  bibliophiles  call  extra  illustration  of 
some  book,  they  are  bound  to  suggest  mere  ornamentation  of 
some  pre-eminently  worthy  nucleus,  and  the  whole  anatomy 
of  chemical  instruction  must  be  deformed. 

b.  For  holding  Interest  and  Attention : — The  whole  psychology 
of  laboratory  work  forms  an  interesting  study  in  itself.    Without 
attempting  to  treat  the  subject  fully,  we  may  draw 
attention  to  one  fact  at  least  which  contributes  to  of  Laboratory 
its   value  as  a  means  of  instruction.  |_  During   the  study* 
performance  of  an   experiment,  unless   it   is  an  exceptionally 
tedious  one,  it  is  almost  impossible  for  the  interest  6f  the  pupil 
to  be  withdrawn,  or  for  his  attention  to  flag.     The  operations 


92  INSTRUCTION  IN  THE  LABORATORY 

being  performed,  the  changes  being  watched,  and  the  legitimate 
curiosity  in  regard  to  what  will  happen  next,  keep  the  whole 
matter  constantly  in  the  centre  of  the  pupil's  field  of  conscious- 
ness, and  effectually  prevent  mind  wandering.  The  strain  on 
the  pupil's  powers  of  voluntary  attention,  which  book  work 
brings  with  it,  is  thus  avoided  in  a  large  part  of  the  time  devoted 
to  the  study  of  chemistry.  His  thought  about  the  subject  also, 
with  the  activity  continually  prompted  by  this  thought,  satisfies 
the  psychological  demand  for  reaction  as  the  necessary  correla- 
tive of  reception. *J 

(^Professor  Devvey  has  pointed  out  another  advantage  which 
the  laboratory  possesses  over  the  book,  inasmuch  as  the  per- 
formance of  an  experiment  entirely  diverts  the  attention  of  the 
pupil  from  the  thought  that  he  is  studying,  and  fixes  it  com- 
pletely on  that  which  is  being  studied.)  In  other  ways  of  learn- 
ing, the  thought  that  he  is  studying  is  continually  in  danger  of 
approaching  a  focal  position  in  the  field  of  consciousness,  and 
relegating  the  object  of  study  to  a  less  central  position,  and  even 
occasionally  banishing  it  altogether. 

c.  For  Securing  Clear  and  Pregnant  Expression: — In  most  stud- 
ies we  begin  with  the  expression  of  the  fact,  and  seek  by  study  of 
the  statement  to  reach  the  fact  itself.  In  practical 
fronfract  to  science>  we  encounter  the  fact  first,  and,  having  the 
Expression  fact  clearly  in  mind,  proceed  to  find  a  suitable  expres- 
and  not  Vice  •  /•  •-  mi  /•  i  •  • 

Versa.  sion  f°r  rt'     ^ne  former  process  is  subject  to  mis- 

understanjdings  which  are  only  too  familiar.    Even  if 
the  language  used  is  fortunately  chosen,  our  personal  equation, 

1  Cf.  James,  Talks  to  Teachers,  Chapter  V.  The  pyschology  of  labo- 
ratory work  has  been  admirably  discussed  by  Newell  in  a  paper  on 
"More  Profitable  High  School  Chemistry."  SCHOOL  REVIEW,  IX. 
(1901),  286.  This  article  contains  an  admirable  application  to  chemistry  of 
the  general  principles  discussed  in  Professor  James'  book.  The  criti- 
cisms of  actual  features  of  chemical  instruction  in  the  light  of  psychologi- 
cal principles  will  be  found  not  only  interesting  but  of  practical  value. 
It  should  be  added  that  the  Talks  to  Teachers  form  the  clearest  presenta- 
tion of  the  application  of  psychology  to  teaching  in  existence,  and  in 
case  it  is  not  familiar  to  the  reader  its  study  cannot  be  urged  too 
strongly. 


INSTRUCTION  IN  THE  LABORATORY         93 

resulting  from  the  associations  we  have  formed  with  the  words, 
may  result  in  more  or  less  distortion  when  we  seek  to  grasp  the 
meaning.  We  are  all  familiar  with  the  game  of  "rumour  "  in  which 
the  final  result  bears  scarcely  any  recognisable  resemblance  to 
the  original.  Much  instruction  is  of  this  kind.  The  teacher 
takes  the  fact  he  intends  to  present  from  a  statement  in  a  book. 
It  went  through  several  stages  even  before  it  reached  his  eye. 
But,  leaving  this  out  of  account,  we  have  first  his  conception  of 
its  meaning,  then  the  expression  which  he  gives  it  in  conveying 
this  conception  to  his  class,  then  the  interpretation  they  put 
upon  his  statement,  and  finally  the  effort  they  in  turn  make  to 
reproduce  it  in  their  own  language.  The  steps  in  this  process 
are  more  than  sufficient  amply  to  explain  the  ludicrous  misap- 
prehensions which  so  often  arise.  (_In  the  laboratory  the  pupil 
encounters  the  fact  directly,  without  the  intermediate  steps  which 
involve  the  teacher,  although  the  latter  is  of  course  concerned  in 
assisting  in  the  thorough  exploration  of  the  fact,  and  so  the  pupil 
is  able  to  express  the  fact  with  much  less  risk  of  falsificationj 

Not  only,  however,  are  direct  apprehension  and  clear  expres- 
sion of  the  facts  of  the  science  thus  the  privilege  of  the  pupil, 
but  the  statement  means  much  more  to  him  after  this  process 
than  it  could  have  done  if  it  had  been  furnished  by  the  teacher 
or  the  book.  Lit  is  not  an  assemblage  of  words  or  a  dead  phrase, 

^rt 

but  a  statement  bristling  with  reminiscence  and  significancey 
When  we  consider  the  limitations  of  language  as  a  mode  of  ex- 
pressing any  idea  with  absolute  precision  and  completeness, 
and  at  the  same  time  without  including  too  much,  the  advan- 
tage of  this  thorough  grasp  of  the  idea  which  has  preceded  the 
expression,  and  must  forever  accompany  its  use,  will  not  require 
further  justification. 

Let  us  illustrate  by  referring  to  one  of  the  commonest  forms 
in   which   the    differences  between  related  substances  are  ex- 
pressed.     The    statement   that   chlorine   is   more  An 
active  thap  bromine,  and  bromine  than  iodine,  is  a  nitration. 
lifeless  platitude  to  one  who  has  no  vivid  experience  with  these 
substances  to  accompany  it  and  give  it  meaning.     After   the 


94  INSTRUCTION  IN  THE   LABORATORY 

elements  have  been  handled,  however,  and  comparison  of  their 
activity  has  been  made  by  studying  the  action  of  chlorine  and 
bromine  on  salts  of  bromine  and  iodine,  for  example,  or  by  com- 
paring the  actions  of  sulphuric  acid  upon  chlorides,  bromides 
and  iodides,  or  by  heating  the  hydrogen  compounds  of  the 
three  elements,  the  word  active  acquires  a  definite  experimental 
significance,  and  the  whole  phrase  becomes  pregnant  with 
information. 

III.     The  Laboratory  Directions. 

Since  it  is  impossible  for  the  teacher  continually  to  supervise 
every  motion  and  thought  of  the  pupil,  his  place  during  the 
greater  part  of  the  work  must  be  taken  by  printed  laboratory 
directions.  On  the  completeness  and  adequacy  of  these  direc- 
tions must  depend  to  a  large  extent  the  realization  of  the  pur- 
poses just  discussed.  If,  for  example,  the  instructions  confine 
themselves  to  the  barest  statement  of  what  materials  shall  be 
brought  together,  the  pupil's  experience  will  be  utterly  insuffi- 
cient to  furnish  him  with  a  conception  of  how  best  to  perform 
the  operation,  of  what  to  look  for  and  when  to  look  for  it,  and 
of  the  relations  of  the  things  he  sees  to  one  another  and  to  his 
previous  experience.  The  existing  laboratory  manuals  show  all 
sorts  of  directions,  from  the  most  meagre  to  the  over-elaborate. 
It  is,  at  all  events,  necessary  that  the  teacher  should  carefully  con- 
sider the  directions  in  the  book  he  uses,  and  adapt  himself  to 
them  by  preliminary  discussion  of  the  experiment.  If  need  be 
he  must  give  supplementary  directions  written  on  a  blackboard, 
or  perhaps  substitute  a  more  appropriate  form  in  mimeograph 
sheets.  The  difficulty  which  this  problem  presents  will  be  seen 
when  we  consider  all  the  demands  which  may  fairly  be  made  on 
a  good  outline. 

a.  Laboratory  Directions  Should  be  Coherent :  —  The  chief  fault 
of  laboratory  study  is  its  tendency  to  resolve  itself  into  a  series 
of  isolated,  and  therefore  mechanical,  proceedings.  The  phrase 
we  so  commonly  hear,  that  a  pupil  has  performed  fifty  or  a 
hundred  experiments,  suggests  that  this  disintegration  may  by 


INSTRUCTION  IN  THE  LABORATORY         95 

some  be  considered  a  merit  rather  than  otherwise.  Fifty  ex- 
periments may  contain  the  material  for  the  development  of  a 
knowledge  of  the  typical  principles  of  chemistry,  Disadvantage 
just  as  fifty  sleight  of  hand  tricks  may  contain  the  basis  of  inconer- 
for  the  study  of  the  psychology  of  illusion,  but  in  both  ence* 
cases  there  must  be  a  great  distance  to  be  covered  before  the 
results  of  the  separate  mechanical  proceedings  have  been  organ- 
ized into  a  knowledge  of  either  science.  Evidently  a  long  step 
can  be  taken  in  the  right  direction  by  arranging  the  operations 
in  groups,  with  an  idea  running  through  each  group,  so  that  it 
shall  constitute  a  study  of  some  element  or  compound,  or  of  the 
material  for  the  development  of  some  generalization.  An  ex- 
ample will  show  how  a  series  of  experiments,  by  proper  grouping, 
may  be  converted  into  a  systematic  study. 

Suppose  that  chlorine  is  the  subject.  The  first  question 
has  to  do  with  the  ways  in  which  it  may  be  prepared.  It  may 
not  be  possible  conveniently  to  illustrate  all  the  dis-  mustration 
tinct  methods  in  the  laboratory.  The  electrolysis  Chlorine, 
of  solutions  of  chlorides,  for  example,  may  be  reserved  for  the 
demonstration.  But  the  common  general  method,  consisting  in 
the  oxidation  of  some  chloride,  will  naturally  be  given.  It  is  as 
easy  for  the  pupil  to  take  half  a  dozen  test-tubes,  and  place  in 
them  various  substances,  like  potassium  chlorate,  minium, 
barium  peroxide,  potassium  dichromate,  etc.,  and  to  treat  each 
with  hydrochloric  acid,  as  to  perform  the  same  experiment  with 
one  of  them.  The  view  of  the  nature  of  the  action  will  be 
broadened  by  further  comparing  the  effect  of  litharge  with  that 
of  minium,  and  of  some  metallic  chloride  and  sulphuric  or 
phosphoric  acid  with  that  of  hydrochloric  acid.  The  results 
naturally  lead  later  to  an  instructive  discussion  of  the  meaning 
and  mechanism  of  oxidation  in  this  case. 

Following  this  will  naturally  come  the  main  preparation  of  a 
quantity  of  chlorine  for  the  examination  of  its  properties  and  the 
performance  of  some  of  the  usual  experiments  with  it.  It  may 
be  noted  that  the  union  with  phosphorus,  antimony,  and  other 
elements  are  not  distinct  properties,  but  illustrations  of  one 


96          INSTRUCTION  IN  THE  LABORATORY 

property,  namely,  the  great  activity  it  exhibits  in  uniting  with 
various  elements.  Other  distinct  properties  are  its  tendency 
to  act  upon  water,  forming  a  small  amount  of  hypochlorous  acid 
(H2O  +  C12  ;±  HC1  +  HC1O — Note  that  the  actiofl  of  light 
on  the  solution  is  due  to  decomposition  of  the  hypochlorous 
acid  and  is  not  a  property  of  chlorine),  its  tendency  to  replace 
hydrogen  in  organic  compounds,  etc. 

It  will  be  noted  that  experiments  giving  negative  results,  like 
the  action  of  litharge  above,  are  useful  rather  than  objectionable, 
'•'hey  are,  indeed,  necessary  in  order  that  a  basis  for  comparison 
may  be  furnished. 

In  a  similar  way  the  study  of  hydrates,  commonly  spoken  of 
as  substances  containing '  water  of  crystallization,'  requires  a  num- 
ber of  closely  related  experiments  in  order  that  a 
Illustration,  .  f  l  ,.  . 

Water  of         basis  for  really  understanding  the  subject  may  be 

Crystalliza-  furnished.  We  have  to  note,  first,  that  a  body  like 
blue  vitrol  can  be  decomposed  by  heating  and  the 
product  has  entirely  new  properties ;  second,  that  this  anhy- 
drous material  combines  with  water  and  the  mixture  furnishes 
crystals  like  the  original  ones ;  third,  that  the  proportion  used 
in  combination  can  be  expressed  ultimately  in  terms  of  com- 
bining weights,  proximately  in  terms  of  the  formula  weights  of 
water  and  the  salt,  and  is  therefore  genuine  chemical  com- 
bination ;  fourth,  that  the  same  substance  may  have  crystalline 
form,  of  a  different  kind  however,  without  containing  water 
(it  may  be  crystallized  from  concentrated  sulphuric  acid)  ; 
finally,  a  number  of  crystalline  substances  may  be  examined  by 
heating  in  order  to  ascertain  which  are  and  which  are  not 
hydrates  in  the  common  form  in  which  they  are  sold. 

There  is  no  objection  to  the  numbering  of  experiments. 
This  is  indeed  an  advantage  to  the  teacher  when  examining  the 
note-books.  The  point  we  have  tried  to  make  is,  that  the  work 
must  be  grouped,  and  the  groups  must  be  coherent,  in  order 
that  the  results  may  be  such  that  they  furnish  material  for  com- 
parison, discrimination,  and  the  arrangement  in  logical  relation 
of  the  observed  facts.  When  the  results  are  assembled  in  such 


INSTRUCTION  IN  THE  LABORATORY          97 

a  fashion,  the  material  is  ripe  for  generalization.  This  final 
step  will  not  usually  be  taken  by  the  pupil,  even  if  he  is  invited 
to  take  it.  The  review  of  the  work  in  the  quiz  will  be  needed  to 
bring  out  the  relations  more  clearly,  and  in  this  exercise  there- 
fore the  first  development  of  generalizations  will  usually  occur. 

b.  Main  Points  in  Regard  to  the  Directions  for  each  Experi- 
ment:—  The  main  features  which  are  required  to  constitute 
proper  direction  in  each  experiment,  and  which  must  be  fur- 
nished either  by  the  manual,  the  teacher,  or  the  head  work  of 
the  pupil,  may  be  summed  up  very  briefly. 

First,  the  object  of  the  experiment  must  be  definitely  stated, 
•  -r  at  least  clearly  implied  in  the  title.  Except  in  the  case  of 
v  crification  of  a  law,  however,  it  is  obvious  that  the  result  of  the 
experiment  should  be  carefully  concealed. 

Second,  the  apparatus  must  be  lucidly  described,  and  if 
possible  illustrated,  in  order  that  it  may  be  readily  constructed 

without  loss  of  time  :  the  object  of  the  various  parts  ^ 

J  Directions  in 

should  be  mentioned  in  case  any  of  them  are  new,  regard  to 
or  are  not  likely  to  be  understood  at  once.  Manipulation. 

Third,  a  minute  and  practical  description  of  the  materials 
must  be  given.  The  quantity  should  be  stated  precisely,} to 
avoid  the  tendency  which  the  pupil  generally  has  at  the  start  to 
use  four  or  five  times  too  much ;  he  should  be  shown  that  this 
results  not  simply  in  waste  of  material,  but,  what  is  much  more 
important,  in  great  waste  of  time.  If  solutions  are  concerned, 
the  concentration  to  be  used  should  be  given  :  it  will  be  noted 
that  in  general  chemistry,  unlike  qualitative  analysis,  one 
strength  will  not  serve  for  all  experiments.  Inasmuch  as  the 
state  of  many  materials  differs  in  different  samples,  the  outline 
should  specify  whether  an  anhydrous  or  crystallized  variety  is  to 
be  used,  whether  the  zinc  is  to  be  common  granulated  or 
chemically  pure,  or  in  the  form  of  zinc  dust,  and  whether  lumps 
of  the  substance  will  serve  the  purpose,  or  whether  it  must  be 
powdered.  The  great  difference  in  the  results  depending  on 
these  things  may  be  pointed  out  when  opportunity  offers  (pp. 
102,  131). 

7 


98  INSTRUCTION  IN  THE  LABORATORY 

Fourth,  the  handling  of  the  material  and  apparatus  must  be 
made  clear.  In  simple  cases  like  precipitation,  for  example, 
the  very  gradual  addition  of  the  reagent,  accompanied  by  con- 
tinual agitation,  must  be  directed  to  avoid  confusion.  The 
curious  layers  which  otherwise  arise  may  else  become  the 
subject  of  observation  and  divert  the  attention  into  fruitless 
channels.  Perhaps  a  special  exercise  on  this  is  advisable.  When 
the  experiment  is  elaborate,  minute  directions  are  even  more 
necessary. 

The  three  last  points  are  concerned  with  the  peculiarity  of 
chemical  work,  that  the  subject  of  observation  has  to  be  created 
by  the  pupil,  and  the  lesson  it  may  teach  cannot  be  reached 
unless  care  is  taken  that  the  data,  consisting  in  the  phenomena 
observed,  shall  be  specific  and  identical  in  every  repetition  of 
each  experiment. 

Fifth,  the  point  at  which  a  pertinent  observation  may  be 
made  should  be  indicated  by  an  interrogation  mark,  or  in 
Directions  some  other  way.  In  one  experiment  the  pupil 

concerning  may  acidify  a  solution  *and  then  add  hydrogen 
Observation  J  J 

and  sulphide ;   in  the  next  he  may  use  zinc  sulphate 

Inference.  an(j  ^^  sodjum  hydroxide,  first  in  small  amount, 
and  ^  then  in  excess.  The  slight  alteration  in  the  appearance 
which  the  acid  may  produce  will  leave  him  in  doubt  as  to 
whether  it  has  <any  significance,  and  should  be  made  a  basis  of 
inference  or  not ;  and  if  he  decides  that  it  should  not,  it  may 
happen  that  the  first  effect  of  the  sodium  hydroxide  will  be  so 
slight  that  he  will  neglect  it  also.  Since  the  acid  simply  added 
hydrogen  ions,  while  the  sodium  hydroxide  produced  a  definite 
change,  an  interrogation-mark  will  call  attention *to  the  latter 
fact. 

:  Sixth,  some  indication  is  necessary  as  to  what  is  to  be  ob- 
served:  for  example,  the  use  of  the  nose  has  to  be  enjoined 
many  times  before  it  becomes  habitual  in  almost  every  experi- 
ment. Similarly  it  is  sometimes  necessary  to  draw  attention  to 
a  change  in  colour  which  may  represent  a  passing  stage  in  a 
chemical  change,  or  to  the  production  of  a  gas  which  might  be 


INSTRUCTION  IN  THE  LABORATORY         99 

overlooked,  as  in  the  addition  of  a  soluble  carbonate  to  many 
salts  of  heavy  metals.  Perhaps  separate  exercises  on  these 
details  of  observation  would  be  advisable,  in  order  that  the 
pupil  may  afterwards  be  left  more  completely  to  think  for 
himself  in  later  experiments. 

Finally,  definite  questions  should  be  asked  in  regard  to  the 
interpretation  of  what  has  been  observed.  These  should  be  of 
two  kinds  which  should  be  distinguished  plainly  from  one  an- 
other. Some  it  may  be  possible  to  answer  from  the  observa- 
tions and  previous  knowledge  of  the  pupil  alone ;  others  may 
require  reference  to  a  book  for  part  of  the  data.  The  pupil 
cannot  tell,  without  some  suitable  indication,  of  which  variety 
the  question  is,  and  will,  in  general,  in  every  case  make  use  of 
the  book,  and  so  miss  the  opportunity  of  thinking  for  himself, 
which  the  former  variety  of  question  would  encourage  him 
to  do.1 

It  is  evident,  of  course,  that  some  mean  must  be  struck  be- 
tween over-elaboration  and  too  great  compression  of  the  in- 
structions. They  must  not  be  so  minute  that  to  follow  them 
will  be  wearisome,  or  so  complicated  as  to  4>e  distracting  and 
unworkable.  If  too  concise,  they  will  put  more  responsibil- 
ity upon  the  teacher  and  pupil  than_  the  size  of  the  class 
in  the  former  case,  or  the  intelligence  in  the  latter  case,  will 
stand.  f 

It  is  evident  also  that  detailed  directions  will  not  be  given  in 
connection  with  every  problem.  In  many  cases  the  question 
will  be  stated  and  the  pupil  will  be  left  to  devise  his  own  experi- 
mental method  of  attacking  it  and  to  do  most  of  the  thinking 
involved  for  himself.  With  large  classes  problems  of  this  kind 
can  be  given  only  after  much  carefully  directed  work  has  been 
accomplished.  With  small  classes,  on  the  other  hand,  or  when 
trained  assistance  is  available,  the  more  independent  method 
may  be  used  almost  from  the  start  and  with  the  very  best 
results. 


1  This  question  is  discussed  more  fully  under  Use  of  the  Text-book, 
chapter  V.,  section  d  (p.  136). 


100        INSTRUCTION  IN   THE  LABORATORY 

c.  Selection  of  Experiments  :  -  In  general  the  selection  of  the 
experiments  should  be  made  so  as  to  afford  the  pupil  oppor- 
Considera-  tumty  to  handle  and  become  acquainted  with  all 
tions  affect-  important  substances,  and  to  furnish  him  with  mate- 
ing  selection.  .  ,  r  •  •  i  r  i 

rial  for  systematic  study  of  each  topic  m  order  that 

some  material  for  generalization  may  be  available.  Such  chem- 
ical changes  only  should  be  used  as  may  surely  be  brought 
about  when  the  conditions  are  definitely  specified.  The  inclu- 
sion of  a  fact  should  be  determined  by  its  value  for  the  pur- 
pose in  view,  and  not  because  it  is  easy  to  show,  or  because 
its  presentation  is  sanctioned  by  custom.  The  experiment 
should  reach  the  point  to  be  illustrated  as  directly  as  possible. 
Thus  measurement  of  substances  by  observing  the  volumes  of 
solutions  is  less  direct  than  weighing,  since  the  latter  is  the  mode 
of  measurement  in  terms  of  which  chemical  quantities  are  de- 
fined. Gravimetric  experiments  should  therefore  precede  volu- 
metric. Artificial  methods  should  be  replaced  by  natural  when 
possible.  For  example,  making  sulphuric  acid  from  sulphur 
dioxide  obtained  from  sulphuric  acid  does  not  illustrate  the 
commercial  process,  and  is  in  itself  stultifying.  It  is  equally 
easy  to  burn  pyrites  (in  a  hard  glass  tube)  in  a  stream  of  air 
drawn  or  driven  over  it. 

Above  all,  the  numerous  limitations  of  the  pupil,  both  in  gen- 
eral and  in  view  of  his  particular  state  of  advancement,  must  not 
be  forgotten.  The  apparatus  which  can  be  furnished  by  the 
laboratory  or  handled  by  the  pupil  must  be  thought  of.  ]  The 
degree  of  skill  and  the  knowledge  which  the  pupil  has  acquired 
must  be  borne  in  mind.  The  length  of  the  periods  available 
for  work  must  frequently  lead  to  the  exclusion  of  some  val- 
uable experiments.  In  discussing  the  results,  the  precautions 
taken  by  the  pupil  must  be  considered  in  the  light  of  the  much 
greater  precautions  which  scientific  work  of  permanent  value 
demands.  The  small  number  of  data  he  obtains,  as  compared 
with  the  mass  of  data  tvhich  alone  can  furnish  a  basis  for  confi- 
dent generalization,  must  be  remembered.  We  shall  presently 
discuss  more  fully  the  incompleteness  of  much  of  the  pupil's 


INSTRUCTION  IN  THE  LABORATORY       IOI 

work  in  consequence  of  these  limitations,  and  the  necessity  for 
leading  him  to  realize  precisely  how  far  he  contributes  to  the 
result,  and  how  far  the  book  is  to  be  called  upon  for  furnish- 
ing an  adequate  foundation  for  the  conclusion  (p.  136,  cf.  also 
p.  99).  All  this  will  be  made  much  clearer  if  some  oppor- 
tunity is  taken  to  explain  in  Detail  some  particular  chemical 
investigation,  with  all  the  laborious  purification  of  materials  and 
analysis  of  multitudes  of  specimens  which  must  be  accomplished 
before  even  comparatively  limited  conclusions  can  be  reached. 
Almost  any  account  of  inorganic  research  l  will  furnish  material 
for  this. 

(The  chief  general  rule  is  that  the  work  should  be,  as  far  as 
possible,  intensive  rather  than  extensive.  _J  A  sufficient  sample 
of  the  whole  ground  covered  by  the  science  must 
be    included,   for  there    are    many  reasons   which   rather  than 


make  this  desirable  in  the  course  given  in  the  ^*™ive 
secondary  school.  But  it  must  be  remembered 
that  a  thorough  knowledge  of  one  small  portion  really  implies 
the  ability  to  master  other  and  different  portions  more  rapidly, 
and  is  therefore,  from  every  point  of  view,  a  thing  desirable  of 
attainment.  The  intensive  method  means  also  that  the  total 
acquisition  must  be  greater,  for  it  is  only  after  we  know  some- 
thing about  some  chemical  substance  that  we  are  able  to  do 
the  most  intelligent  work  with  it.  Nor  is  intensive  work  more 
difficult  than  the  other.  On  the  contrary,  it  is  much  easier  to 
enlarge  our  knowledge  of  a  group  of  closely  related  things,  than 
to  enlarge  it  by  passing  rapidly  from  one  group  to  another  of 
things  which  are  strange  and  less  closely  related.  This  instruc- 
tion may  tax  the  power  of  the  teacher  more,  but  it  must  be  less 
difficult  for  the  pupil.  A  Cook's  excursion  covering  ten  cen- 
turies of  time  and  ten  square  miles  of  area  in  a  single  day  is 
notoriously  not  the  best  means  of  studying  the  history  and  soci- 
ology of  a  people  and  its  institutions.  Laboratory  work  which 
resembles  a  personally  conducted  glance  at  many  different  things, 


1  For  list  of  papers,  see  chapter  VIII.,  section  III.  (p.  214). 


102        INSTRUCTION  IN   THE  LABORATORY 

may  leave  a  confused  sense  of  many  more  or  less  interesting 
impressions,  but  it  cannot  furnish  an  opportunity  for  learning 
chemistry. 

It  is  this  superficial  quality  which  much  school  work  possesses 
that  prevents  its  recognition  by  the  colleges.  If  the  study  of 
Latin  in  the  school  were  of  the  same  flimsy  nature,  and  included 
no  genuine  investigation  of  the  text,  no  mastery  of  the  thing 
itself,  and  no  adequate  acquaintance  with  it  in  all  its  complexity 
as  a  medium  of  communicating  thought,  it  would  receive  no 
recognition  either.  Both  subjects  must  submit  to  the  same 
test  of  educational  value,  or  the  whole  work  must  be  done  over 
again  in  college.  As  Professor  Bard  well  says,1  speaking  of  chem- 
istry, "  ingenuity  and  initiative  power  .  .  .  come  to  the  student 
not  ...  by  looking  through  experiments  to  greater  things  be- 
yond, but  by  looking  into  experiments  to  find  the  simpler  things 
which  are  near  at  hand."  The  same  may  be  said  of  any  of  the 
benefits  the  study  of  the  subject  may  confer.  The  limit  of  in- 
tensive study  is  to  convert  the  whole  work  into  research  'and 
give  up  the  idea  of  covering  much  ground.  My  point  is  that 
both  features  must  be  preserved,  and  that  of  the  two  the  former 
is  the  more  important. 

d.  An  Illustration :  —  In  a  well-known  laboratory  outline 
I  find  the  following  :  "  Treat  a  few  small  crystals  of  potassium 
iodide  with  concentrated  sulphuric  acid.  What 
iodide  and  do  you  notice?  Compare  with  the  results  ob- 
Suiphuric  tained  when  potassium  bromide  and  sodium  chlo- 
ride were  treated  in  a  similar  way."  This  brief 
statement  constitutes  the  whole  directions  for  the  experiment.2 
I  have  found  this  apparently  simple  experiment,  at  least  at  the 
stage  at  which  it  naturally  appears  in  the  course,  by  far  the  most 
difficult  of  the  whole  series  for  the  year.  In  the  first  place,  if 

1  New    England  Association  of  Chemistry  Teachers,   Report  of  the 
Sixth  Meeting,  3. 

2  It  ought  to  be  said  that  the  author  of  the  book  does  not  profess  to 
offer  the  sort  of  directions  combining  instruction  with  direction  which  we 
have  advocated.     He  says  expressly  that  everything   has  been  omitted 
tliat  "  does  not  serve  to  insure  the  success  of  the  experimental  work." 


INSTRUCTION  IN  THE  LABORATORY        103 

rather  large  crystals  are  taken,  with  much  acid,  and  heat  is  not 
applied,  no  noticeable  amount  of  gas  may  be  given  off  at  all. 
To  get  uniform  results,  the  salt  must  be  powdered  and  simply 
moistened  with  acid,  and  heating  must  be  suggested  in  case 
the  pupil  does  not  get  more  results  than  he  can  take  care  of 
without  this.  In  the  second  place,  the  pupil  observes  fuming 
in  the  air  outside  the  mouth  of  the  tube,  a  violet-coloured 
vapour  in  the  tube,  a  brown  film  on  the  walls  of  the  tube,  an 
odour  (sulphur  dioxide  or  hydrogen  sulphide,  or  both),  and 
often  a  yellow  sublimate  (sulphur).  Unless  he  is  warned,  he 
supposes  that  one  body  has  all  these  properties.  Without 
guidance  he  will  never  realize  that  from  three  to  five  distinct 
products  are  concerned.  In  the  third  place,  he  may  not  have 
yet  met  with  free  iodine,  sulphur  dioxide,  or  hydrogen  sulphide, 
or,  if  he  has  studied  them,  he  will  have  forgotten  the  properties 
of  the  last  two.  He  certainly  must  have  encountered  hydrogen 
chloride,  but  he  has  probably  forgotten  that  it  fumed  in  moist 
air,  and  in  any  case  he  will  not  reason  that,  the  halogens  being 
similar  elements,  the  new  fuming  gas  must  be  hydrogen  iodide. 
In  the  fourth  place,  he  will  try  to  put  the  whole  of  the  products 
into  one  equation,  and  involve  himself  in  an  arithmetical  puzzle 
of  some  difficulty,  as  well  as  a  chemical  absurdity.  In  the  last 
place,  he  will  fail  to  infer  the  oxidizing  power  of  sulphuric  acid 
and  the  easy  oxidizability  of  the  iodides,  unless  he  is  invited  to 
do  so. 

I  question  the  advisability  of  giving  this  experiment  in  ele- 
mentary work  at  all.  But  in  college  work,  to  prevent  the  pupils 
being  hopelessly  muddled  and  discouraged,  I  have  been  led 
gradually  to  elaborate  the  directions.  They  have  reached  the 
following  form,  which  will  serve  as  an  illustration  of  the  sort  of 
thing  which  is  required  to  secure  intelligent  practical  study  of 
any  problem  :  — 

"  Place  about  a  gram  of  powdered  iodide  of  potassium  in  a 
test-tube   and   moisten    it  with   concentrated   sul-   Model  of 
phuric  acid  (?).     Warm,  if  necessary.     Investigate   Directions, 
the  result  as  follows  :  — 


104        INSTRUCTION  IN  THE  LABORATORY 

"  a.  Breathe  across  the  mouth  of  the  test-tube  to  ascertain 
the  effect  of  the  gas  on  moist  air.  What  gas  previously  made 
showed  the  same  behaviour?  Remembering  the  similarity 
between  the  halogens  and  between  their  corresponding  con> 
pounds,  what  do  you  infer  in  this  case?  To  confirm  this  con- 
clusion, lower  a  glass  rod  dipped  in  ammonium  hydroxide 
solution  into  the  test-tube  (  ?)  :  also  a  strip  of  filter  paper  dipped 
in  lead  nitrate  solution  [R]  (?).x 

"  b.  What  is  the  colour  of  the  gas,  or  any  part  of  it  ?  What 
is  the  coloured  body  ?  (This  assumes  that  iodine  has  been  han- 
dled before.)  Was  there  any  corresponding  product  when 
sulphuric  acid  acted  on  a  chloride  ?  By  what  kind  of  chemical 
action  could  this  coloured  substance  be  formed  from  the  one 
identified  in  a? 

"  c.  Study  the  odour  of  the  gas  and  describe  it  (?).  Was 
there  any  effect  on  the  lead  nitrate  which  remained  unex- 
plained in  #?  Can  you  now  explain  it  [R]?  (This  [R]  as- 
sumes that  hydrogen  sulphide  has  not  yet  been  studied.) 

"  The  work  in  a  and  b  leads  to  the  recognition  of  two  distinct 
gaseous  products.  That  in  c  will  yield  one,  and  perhaps  two 
others.  Still  another  distinct  solid  product  may  be  observed 
on  the  walls  of  the  tube  (?).  Construct  separate  equations 
representing  the  formation  of  the  first  product  from  the  orig- 
inal materials,  and  of  each  of  the  others  from  this  product  and 
sulphuric  acid.  What  two  properties  of  sulphuric  acid  and 
what  property  of  hydrogen  iodide  are  illustrated  by  this  set  of 
experiments."  2 


1  [R]  indicates  that  the  pupil,  in  understanding  what  he  is  asked  to  do 
or  in  interpreting  the  result,  needs  information  he  cannot  have  gained  in 
previous  work,  and  must  therefore  refer  to  some  book  or  to  the  instructor. 
Here  he  is  ignorant  of  the  action  of  iodides  on  lead  salts. 

2  For  examples  of  coherent  directions  and  thorough  working  out  of 
a  problem,    see    the   treatment    of    hydrates    in    Richardson,    6-8,   of 
mechanical  mixture  and  chemical  combination  in  Remsen  and  Randall, 
7-10,  and  of  chalk   in    Perkin    and   Lean,    chapters    XIX.  and  XXX. 
A  large  proportion  of  the  work  in  E.  F.  Smith  and  Kellar  (Experiments 
in  General  Chemistry,  Philadelphia,   Blakiston)  and  Volhardt  and  Zim- 


INSTRUCTION  IN  THE  LABORATORY     .  105 

IV.     The  Pupil  and  his  Attitude. 
BIBLIOGRAPHY   OF   HEURISTIC   TEACHING. 

Second  Report  of  the  Committee  of  the  British  Association  on  The 
Present  Methods  of  Teaching  Chemistry.  Report  of  the  British  Asso- 
ciation, 1889.  Also  published  separately  by  the  Association.  London. 
1889. 

Third  Report  of  Same  Committee,  with  additions  by  Professor  H.  E. 
Armstrong.  Report  of  the  British  Association,  1890.  Reprinted  in 
NATURE,  XLIII.  (1891),  593. 

Armstrong,  H.  E.  On  the  Heuristic  Method.  Special  Reports  on 
Educational  Subjects,  vol.  II.  Printed  for  H.  M.  Stationery  Office,  Lon- 
don, and  sold  by  Eyre  &  Spottiswoode.  1898. 

The  46th  Report  of  the  Department  of  Science  and  Art.  Printed 
for  H.  M.  Stationery  Office,  London,  and  sold  by  Eyre  &  Spottiswoode. 
1899.  Abstract  in  NATURE,  LX.  (1899),  381. 

Picton,  Harold.  The  Great  Shibboleth.  SCHOOL  WORLD,  London, 
vol.  I.,  Oct.  and  Nov.,  1899. 

Perkin,  W.  H.  Vice-Presidential  Address  before  the  Chemical  Sec- 
tion. Report  of  the  British  Association,  1900.  Reprinted  in  NATURE, 

LXII.477- 

Discussion  in  THE  SCHOOL  WORLD,  II.  (1900),  358,396,  437,  476.  The 
last  letter,  by  C.  M.  Stuart,  gives  an  instructive  illustration  in  detail. 

Syllabus  of  an  Elementary  Course  in  Physics  and  Chemistry,  issued  by 
the  Incorporated  Association  of  Headmasters.  London,  Whittaker  &  Co. 
1900. 

Syllabus  of  an  Advanced  School  Course  in  Physics  and  Chemistry, 
issued  by  the  Incorporated  Association  of  Headmasters.  London,  Whit- 
taker  &  Co.  1899. 


Whether  we  consider  the  best  means  of  awakening  and  sus- 
taining interest,  or  of  fostering  the  scientific  habit  of  thought, 
it  is  evident  that  leading  the  pupil  to  adopt  the  attitude  of  a 
discoverer  will  be  most  likely  to  accomplish  the  result  desiredjf 
At  the  same  time  there  are  parts  of  the  subject  to  which  this 
method  of  approach  is  inapplicable.  If,  for  example,  we  sug- 
gest that  the  pupil  should  discover  the  fundamental  laws  of  the 
subject  for  himself,  we  are  putting  upon  him  an  impossible  task, 
and  indeed  deceiving  him  in  regard  to  the  nature  of  the  foun- 

mermann    (Experiments  in    General   Chemistry,    Baltimore,   The    John 
Hopkins  Press)  illustrates  these  qualities  admirably. 


106        INSTRUCTION  IN  THE  LABORATORY 

dation  of  a  law.  Verification  is  the  term  more  applicable  to 
work  in  this  direction.  Nor  would  we  even  suggest  that  the 
whole  of  the  ordinary  facts  should  be  approached  by  the 
method  of  "  find  out  for  yourself,"  for  the  progress  by  this  plan 
would  be  too  slow  for  the  purposes  of  a  secondary  school 
course.  Much  may  be  furnished  in  the  class  room,  but 'the 
laboratory  work  should  be  divided  between  a  small  amount 
of  verification  and  a  large  amount  of  what  may  be  called 
investigation.  ) 

a.  The   Verification  of  Laws :  —  When  the  purpose  of  an 
experiment   is   the   verification   of  a  law,  it  will  naturally  be 
preceded  by  a  careful  study  of  the  facts  which  the  law  covers.1 
While  this  necessarily  carries  with  it  full  knowledge  of  the  re- 
sult of  the  experiment,  it  does  not  deprive  the  experiment  of 
any  of  its  value.     Practical  illustration  will  be  required  in  order 
to  make  the  understanding  of  the  law  more  vivid,  the  recollec- 
tion of  its  content  more  lasting,  and,  above  all,  to  show  by 
means  of  a  sample,  admittedly  rough,  what  the  general  nature 
of  its  experimental  basis  is. 

b.  2  he  Attitude  of  Discoverer :  the  Heuristic  Method : 2  —  It  is 
evident  that  the  nature  of  the  directions  will  have  much  to  do 

with  the  attitude  of  the  pupil  towards   his    work. 
Outline  of  . 

Heuristic         In  the  ideal  application  of  this  method,  however, 

Work'  no  book  and  no  directions  are  used.     The  ques- 

tions to  be  solved  are  suggested  as  far  as  possible  by  the  pupils 
themselves  in  the  course  of  the  examination  of  materials  given 
to  them.  Naturally  the  demands  made  upon  the  pupil  must 
be  graduated,  and  at  first  the  questions  must  be  very  simple. 
An  outline  prepared  by  Professor  Armstrong  (Second  B.  A. 
Report)  will  serve  for  illustration.  Natural  objects  are  ex- 
amined, their  origin,  manufacture,  and  uses  discussed,  their 
appearance  described.  This  is  the  first  stage.  Next,  measure- 
ments of  length,  area,  weight,  density,  temperature,  and  so  forth 


1  Report  of  the  Committee  of  Nine.     University  of  the  State  of  New 
York,  High  School  Bulletin  No.  7,  710. 
2  Cf.  pp.  19,  54  and  56. 


INSTRUCTION  IN   THE  LABORATORY        IO/ 

are  made.  This  is  the  second  stage.  Then  the  effect  of  heat 
on  many  things  is  examined  for  the  purpose  of  gaining  experi- 
ence. Metals  are  heated  in  various  ways ;  wood  is  dried  and 
then  burned  for  examination  of  the  ash  ;  minerals,  such  as  sand, 
clay,  sulphur,  etc.,  are  also  heated.  This  is  the  third  stage,  and 
prepares  for  the  fourth  or  problem  stage  in  which  the  study  of 
some  chemical  change  may  first  be  taken  up. 

The  first  chemical  problem  is  that  of  determining  what  happens 
when  iron  rusts.  The  pupils  must  not  only  "  find  out  for  them- 
selves," but  as  far  as  possible  be  led  to  imitate  the  detective's 
method,  and  find  out  how  to  find  out  for  themselves.  The  ques- 
tion of  the  relative  progress  of  rusting  in  moist  and  dry  filings  may 
suggest  itself.  Or  air  without  water  (dry)  and  water  without 
air  (boiled)  may  be  tried.  Then  the  iron  may  be  weighed  be- 
fore and  after  rusting,  and  the  search  for  the  extra  material  begun. 
The  question  will  be  whether  air  or  water  furnishes  the  material. 
Moist  iron  tied  up  in  muslin  may  be  rusted  in  a  pickle  bottle 
inverted  over  water.  The  disappearance  of  part  of  the  air  leads 
to  the  treating  of  the  same  air  with  fresh  filings,  and  of  the  same  fil- 
ings with  fresh  air,  to  see  whether  the  change  in  either  substance 
reaches  a  limit.  The  experiments  may  include  other  metals, 
and  be  extended  in  various  ways  according  to  the  questions 
which  suggest  themselves  to  the  pupils. 

With  a  little  care  a  series  of  interesting  problems  of  this  kind 
can  be  arranged  in  such  a  way  that  the  solution  of  the  preced- 
ing problems  brings  the  pupil  within  measurable  Nature, 

distance  of  the  solution  of  the  next.     When  suffi-  Limitations, 

and  Results  of 
cient  skill  has  been  acquired,  the  quantitative  stage  Heuristic 

will  be  entered  upon.  Work* 

While  in  this  way  a  large  amount  of  chemistry  may  be 
learned,  the  object  is  not  to  teach  chemistry,  but  to  teach  the 
pupils  how  to  learn,  —  to  confer  ability  and  not  knowledge.  The 
progress  in  one  sense  will  be  slow,  but  the  work,  as  long  as 
interest  is  maintained  and  rational  thinking  and  experimenting 
goes  on,  is  fulfilling  its  mission-  It  cannot  be  objected  that 
this  kind  of  study  is  too  difficult,  for  experience  shows  that  it 


108        INSTRUCTION  IN  THE  LABORATORY 

can  be  done  even  by  young  children.  Picton  ( The  Great  Shib- 
boleth )  has  outlined  a  course  of  this  kind  in  chemistry  for  boys 
about  twelve  years  old  which  he  finds  to  work  admirably.  He 
says  (SCHOOL  WORLD,  II.,  397),  "My  experience  is  that 
the  young  boy  of  nine  or  ten  can  be  readily  got  to  think ;  the 
boy  who  has  had  considerable  school  training  on  ordinary  lines 
can  only  rarely  be  got  to  think  at  all." 

Illustrating  the  really  remarkable  way  in  which  children,  to 
whom  text-books  are  quite  unknown,  will  prove  successful  in  the 
solution  of  intricate  problems,  a  correspondent  in  the  SCHOOL 
WORLD  (II.,  397)  mentions  four  boys  who,  after  two  terms' 
work  in  a  physical  laboratory,  investigated  the  rate  of  expansion 
of  water  when  heated  from  o°  upwards.  They  used  two 
methods,  and  got  good  curves  for  the  apparent  expansion. 
They  saw  clearly,  however,  the  relation  between  this  and  the  real 
expansion,  as  it  would  have  been  in  the  absence  of  the  glass  vessel. 
They  tried  first  to  measure  the  expansion  of  the  glass  with  cal- 
lipers between  o°  and  60°,  but,  finding  the  results  not  exact, 
were  at  a  loss  how  to  proceed.  When  it  was  suggested  that 
some  Frenchman  had  determined  the  expansion  of  mercury 
independently  of  the  vessel  containing  it,  the  boys  ransacked 
the  library  and  found  a  description  of  Regnault's  apparatus  and 
results.  After  being  dissuaded  from  repeating  his  experiments, 
they  corrected  their  own  measurements  by  employment  of  his 
table.  The  writer  adds,  "  undoubtedly  the  method  has  its  draw- 
backs. The  'investigation'  above  mentioned  occupied  the 
better  part  of  a  term,  during  which,  no  doubt,  the  boys  might 
have  read  through  some  little  text-book,  or  pottered  through  a 
course  of  ready-made  *  experiments '  on  *  heat.'  It  also 
cost  the  master  ...  a  good  deal  of  labour.  But  he  finds  that 
a  very  little  of  this  sort  of  work  goes  a  very  long  way.  ...  It 
seems  to  confer  a  power  that  is  not  acquired  in  any  other  way. 
The  pupil's  mind  gains  a  freedom,  a  power  of  seeing  things  for 
itself,  an  alertness  and  adaptability  in  turning  to  fresh  matter, 
which  make  great  gaps  in  methodic  knowledge  of  comparatively 
little  importance.  I  have  more  than  once  been  astonished  at 


INSTRUCTION  IN  THE  LABORATORY        109 

the  ease  with  which  boys,  who  have  worked  on  this  plan  within 
a  very  small  range,  have  been  able  to  grasp  the  bearings  of  ex- 
perimental work  in  quite  another  department,  ....  their  eyes 
[seemed]  to  see  things  and  processes  in  themselves,  and  not 
through  the  mists  of  conventional  terminology." 

Since  the  course  of  the  pupil's  inquiries  must  be  as  inde- 
pendent as  possible,  the  direction  which  it  may  take  cannot  be 
foretold.  The  teacher  must  assist  and  guide  with  judgment, 
and,  in  general,  as  little  as  possible.  A  severe  tax,  however,  will 
frequently  be  put  upon  the  breadth  of  his  knowledge  of  the  sub- 
ject, upon  his  time,  and  upon  his  mechanical  skill. 

While  work  exclusively  on  these  lines,  although  pre-eminently 
suited  to  the  needs  of  young  pupils  in  the  nature  work  of  the 
grammar  school  and  below  it,  does  not  furnish  the  Application 
knowledge  of  chemistry  which  is  expected  in  the  ifl  Teaching 
secondary  school,  it  is  evident  that  this  attitude  is 
the  one  to  be  cultivated  when  chemistry  itself  is  being  taught. 
I  imagine  that,  when  hydrogen  is  being  studied,  in  nine  hun- 
dred and  ninety-nine  cases  in  a  thousand  the  pupil  is  informed 
directly  or  indirectly  that  it  comes  from  the  acid.  Suppose 
that,  instead  of  this,  the  question  were  raised  whether  the  hydro- 
gen came  from  the  metal,  the  hydrogen  chloride,  or  the  water. 
If  the  pupil's  experience  had  dealt  with  the  last  of  these  three 
substances  only,  the  problem  would  be  difficult  to  solve.  If 
other  metals  were  tried,  many  would  be  found  to  give  hydrogen. 
Do  these  all  contain  it?  Other  acids  would  give  hydrogen. 
Are  they  the  source  of  the  element?  Substituting  another  sol- 
vent such  as  toluene  prevents  the  appearance  of  hydrogen. 
Was  water  therefore  the  source  of  it  ?  A  little  thought  will 
show  that  a  large  amount  of  careful  original  work  would  be  re- 
quired to  demonstrate  that  the  acid  was  the  source.  In  our 
teaching  we  are  continually  thus  skimming  airily  over  gaps 
which  conceal  not  one  or  two  steps,  but  whole  flights  of  steps, 
all  of  which  would  have  to  be  taken  in  a  scientific  study  of  the 
subject,  although  they  are  superfluous  when  memorization  of 
the  results  is  the  only  object. 


IIO        INSTRUCTION  IN  THE  LABORATORY 

Practically,  the  effort  will  be  to  include  as  much  heuristic  work 
as  possible  in  the  secondary  school  course.  The  spirit  of  it 
should  certainly  be  of  this  kind.  Now  and  then  problems  of  a 
simple  nature  can  even  be  given,  after  the  material  needed  for 
their  solution  has  been  furnished,  and  the  pupil  may  be  left  to  pro- 
vide his  own  directions  for  their  solution.  Thus,  after  equiva- 
lents have  been  measured,  the  pupil  might  determine  the 
proportion  of  zinc  oxide  in  zinc  dust.  Again,  he  might  be 
instructed  to  find  a  solvent  for  some  material ;  he  might  be 
told  to  make  some  salt  in  a  pure  form  from  an  impure  mineral, 
such  as  manganous  chloride  from  manganese  dioxide  ;  or  again, 
he  might  be  asked  to  demonstrate  the  presence  of  one  or  more 
of  the  elements  in  ammonium  carbonate.  The  exercises  in  the 
recognition  of  unknown  substances  (p.  178)  are  problems  of 
the  same  order  and  are  of  the  highest  value. 

c.  Summary :  —  It  is  safe  to  say  that  much  chemical  instruc- 
tion does  not  reach  the  ideal  sketched  in  this  and  the  preceding 

sections  of  the  chapter.     Yet  chemistry  will  never 
The  Ends  of 
Instruction      be  recognised,  nor  will  it  deserve  to  be  recognised, 

and  Means^'  as  Latin  and  other  olcler  studies  are>  either  as  an 
Attaining  element  in  sound  secondary  education,  or  in  work 
preparatory  to  college,  until  it  is  better  organized 
along  lines  like  these.  We  are  only  beginning  to  recognise 
this.  It  is  not  sufficient  to  suggest  more  thorough  work.  The 
pupil  will  be  lost  in  details  without  the  instruction  which  must 
go  with  it.  Yet  if  the  work  is  not  made  more  elaborate,  the 
result  must  be  superficial.  To  fit  the  science  for  its  place  with 
the  older  studies,  we  must  have  guidance  of  a  restrictive  nature, 
which  shall  confine  the  possibilities  of  experiment,  observation, 
and  inference  within  limits  somewhat  like  those  set  by  the  text, 
the  grammar,  and  the  dictionary.  We  must  have  guidance  of 
an  analytical  kind  to  assist  in  the  finding  and  study  of  all  the 
points  to  be  considered  in  each  experiment.  We  must  have 
guidance  of  a  synthetic  nature  to  stimulate  the  inter- relating  of 
various  facts  and  views  brought  out  by  present  and  past  experi- 
ments. All  this  is  necessary  in  order  that  the  instruction  may 


INSTRUCTION  IN   THE  LABORATORY        III 

be  an  imparting  of  organized  knowledge  and  not  a  jumble  sale, 
and  that,  with  the  acquirement  of  an  ever- tightening  grip  on  the 
inner  spirit  of  the  science,  rather  than  an  ever-growing  collec- 
tion of  rag-bag  odds  and  ends,  the  pupil  may  advance  in  the 
profundity  as  well  as  the  area  of  his  knowledge.  This  alone 
can  make  chemistry  a  genuine  means  of  culture  and  a  discipline 
of  real  benefit  in  the  later  work  of  life.  (  We  need  more  detail, 
and  at  the  same  time  more  perspective.  I  The  Latin  language 
cannot  be  studied  by  any  other  method  ;  in  this  lies  its  strength. 
It  seems  to  be  possible  to  think  that  a  study  of  chemistry  which 
is  not  of  this  kind  may  still  be  a  study  of  the  science ;  in  this 
lies  its  weakness.  The  purpose  of  scientific  education  is  the 
application  and  higher  cultivation  of  the  critical  powers  by  com- 
parison, discrimination,  and  reasoning.  It  must  also  exercise 
and  cultivate  the  power  of  scientific  imagination,  for,  without 
this,  no  clear  conception  of  the  chemical  tendencies  of  matter, 
and  the  conditions  which  influence  their  results,  can  be 
formed.  That  criticism  and  imagination  are  required  in  and 
are  strengthened  by  its  study,  when  this  is  prosecuted  in  the 
proper  way,  may  be  claimed  for  chemistry  at  least  as  confidently 
as  for  any  other  study. 

V.     Laboratory  Technique. 

One  of  the  failings  of  chemistry  teaching  is  the  neglect  of 
laboratory  technique.  The  obvious  value  of  neat  and  careful 
work,  and  of  knowing  how  to  adapt  means  to  ends  in  mechani- 
cal matters,  is  so  great,  not  only  on  account  of  its  general  edu- 
cational value,  but  more  especially  because  it  is  absolutely 
indispensable  in  really  instructive  chemical  experimentation, 
that  this  neglect  may  well  seem  astonishing.  It  can  be  ex- 
cused in  any  given  case  only  on  the  ground  that  adequate 
supervision  of  a  large  class  was  impossible.  In  handling  large 
classes  of  pupils  who  have  already  studied  chemistry  for  a  year 
in  the  secondary  school,  I  have,  for  example,  rarely  found  one 
who  had  any  idea  of  how  to  ascertain  whether  a  piece  of 
apparatus  was  air  tight  or  not.  They  usually  blow  into  it  as  if 


112        INSTRUCTION  IN  THE  LABORATORY 

it  were  a  pair  of  bagpipes,  oblivious  of  the  fact  that  a  hole 
nearly  as  large  as  their  own  throat  would  be  necessary  before 
the  defect  would  be  noticeable.  The  rational  way  of  arranging 
the  test,  so  that  in  some  fashion  the  eye  is  the  instrument  used, 
forms  an  instructive  lesson  in  itself. 

A  good  deal  of  attention  is  required  in  teaching  proper 
manipulation.  It  is  long  before  the  pupil  discovers  that  the 

stop-cock  is  meant  for  lowering  the  eras-flame,  as  well 
Manipulation.  I  .  .  .  .  ,  , 

as  for  extinguishing  it,  yet  he  has  continual  oppor- 
tunity to  observe  the  risk  in  boiling  a  small  amount  of  liquid 
in  a  large  vessel  with  a  large  flame.  It  seems  impossible 
to  impress  upon  the  minds  of  some  pupils  the  proper  method 
of  folding  a  filter  paper,  of  cutting  it  to  circular  form,  and 
making  it  invariably  smaller  than  the  funnel.  The  clever  use 
of  the  test-tube  is  a  small  art  in  itself.  The  pupil  should 
learn  the  reason  for  the  employment  of  different  kinds  of 
apparatus,  such  as  retorts,  flasks,  test-tubes,  etc.,  and  in  some 
exercises  should  be  left  free  to  select  or  devise  apparatus  for 
himself.  The  pupil  is  slow  in  learning  the  difference  between 
thick  and  thin  glass  vessels  in  connection  with  the  application 
of  heat.  Repeated  misfortunes  seem  never  to  teach  him  that 
careful  boring  of  corks  and  fitting  of  tubes  takes  no  longer  than 
making  a  funnel-shaped  or  ragged  opening,  and  sometimes 
saves  hours  of  time  in  subsequent  work.  The  laboratory  in- 
structions, no  matter  how  minute,  will  not  secure  the  desired 
result  without  supervision  and  criticism  by  the  teacher.1 

Weighing,  unless  it  has  already  been  learned  in  the  physical 
laboratory,  requires  careful  preliminary  instruction,  if  damage 

to   the   balance   and  discouragement  in   the  work 

are  to  be  avoided.  The  most  frequent  mistakes 
seem  to  arise  from  failure  to  count  the  weights  correctly. 
Special  emphasis  should  be  laid  on  the  necessity  of  ascer- 

1  These  general  operations  are  well  described  by  Newth,  Elementary 
Inorganic  Chemistry,  15-34,  by  Young,  Elementary  Principles  of  Chem- 
istry, Part  II.,  91-104,  by  Newell,  Experimental  Chemistry,  1-9,  329-353, 
and  365-369,  by  Peters,  Modern  Chemistry  (Maynard,  Merrill  &  Co.), 
355-380,  as  well  as  by  many  other  authors. 


INSTRUCTION  IN  THE  LABORATORY       113 

taining  the  weight,  first  by  examination  of  the  vacant  places  in 
the  box,  and  then  checking  by  counting  the  weights  themselves 
as  they  are  replaced.     The  working  of  glass,  even  <jiass_work- 
if  it  go  no  further  than  the  bending  or  drawing  out  tog. 
of  glass-tubing  and  fire-polishing  of  the  sharp  edges,  requires  a 
separate  exercise.     A  Bunsen  burner  on  which  was  inscribed  in 
large  letters,  "  do  not  use  me  in  bending  tubing,"  would  be  a 
boon  to  the  teacher.1 


VI.    Quantitative  Experiments. 
REFERENCES. 

Newell,  Lyman  C.  Quantitative  Experiments  in  Chemistry  for  High 
Schools.  SCHOOL  SCIENCE  (Monthly.  Chicago,  138  Washington  St.), 
I.  12.  This  new  journal  has  already  published  several  valuable  articles 
on  subjects  of  interest  to  teachers  of  chemistry. 

Ramsay,  Wm.  Experimental  Proofs  of  Chemical  Theory  for  Begin- 
ners. London  and  New  York,  Macmillan.  1893. 

Tilden,  W.  A.  Hints  on  the  Teaching  of  Elementary  Chemistry. 
London  and  New  York,  Longmans,  Green  &  Co.  1895. 

Cornish,  Vaughan.  Practical  Proofs  of  Chemical  Laws.  London  and 
New  York,  Longmans,  Green  &  Co.  1895. 

Smith,  Alexander.  Laboratory  Outline  of  General  Chemistry.  Chi- 
cago, The  University  of  Chicago  Press.  1900. 

We  have  already  referred  to  the  emphasis  which  is  neces- 
sarily laid  in  chemistry  upon  quantitative  measurement  and  the 
interpretation  of  the  results.  Imaginary  examples,  as  we  have 
hinted  (p.  80),  may  serve  when  actual  ones  are  not  available,  but 
the  ease  with  which  properly  chosen  measurements  can  be 


1  Clear  instructions  in  regard  to  glass-working  are  given  by  Newth, 
ibid.,  35-39,  by  R.  P.  Williams,  Elements  of  Chemistry  (Ginn  &  Co., 
Boston,  1897),  384-387,  and  by  G.  M.  Richardson,  Laboratory  Manual 
and  Principles  of  Chemistry  (Macmillan,  1894),  225-229.  The  teacher 
will  find  some  accomplishment  in  this  art  invaluable.  It  is  best  acquired 
from  direct  instruction  by  some  glass-blower.  Much  may  be  learned, 
however,  by  the  study  of  works  like  Shenstone's  Methods  of  Glass  Blowing 
(Longmans,  Green  &  Co.,  1897),  or  Threlfall's  On  Laboratory  Arts  (Mac- 
millan, 1898),  chapter  I. 


I  I  ft  I  I  \  1 1~  r-»  r+ 


114        INSTRUCTION  IN   THE  LABORATORY 

carried  out  leaves  little  excuse  for  their  omission,  either  from 
the  demonstration  or  from  the  laboratory  work  of  the  pupil.1 

a.  Limitations : 2  —  It  is  clear  that  the  experiments  chosen 
must  be  such  that  they  are  easily  performed,  and  furnish 
fairly  good  results  in  the  hands  of  beginners.  They  should 
employ  no  complicated  or  expensive  apparatus.  They  should 
be  capable  of  performance  by  a  single  pair  of  hands  within  the 
laboratory  period.  There  is  no  disadvantage,  however,  in  per- 
mitting two  pupils  to  work  together,  provided  they  figure  out 
the  results  separately.  The  most  important  condition  is  that 
it  should  be  possible  to  furnish  the  pupil  with  instructions 
which  will  relieve  the  teacher  of  the  burden  of  continuous 
supervision  of  each  individual. 

The  chief  misunderstanding  which  seems  to  arise  in  connec- 
tion with  this  work  is  a  confusion  of  it  with  quantitative  analysis. 

The  latter  has  for  its  object  the  learning  of  tech- 
The  Degree  of  ...  -       ,    ,         .     .  rr,. 

Exactness       nique  of  the  most  refined  description.     1  he  present 

Required.  experiments  have  for  their  use  the  comprehension 
of  how  quantities  in  chemistry  are  determined.  Of  course 
sufficient  precautions  must  be  taken  to  insure  results  which  are 
approximately  correct,  or  are  at  least  concordant.  It  is 
frequently  objected  that  results  which  are  not  exact  are  not 
only  without  value,  but  are  misleading.  This  seems  to  rest  on 
a  misapprehension.  No  chemical  work  is  absolutely  exact. 
The  conclusion  always  takes  into  consideration  the  sources  of 
error,  "and  the  probable  magnitude  of  the  error,  in  applying  the 
numerical  value  obtained.  There  is  no  reason  why  this  should 
not  be  done  in  the  experiments  of  beginners  also.  Indeed 
it  should  be  one  of  the  most  instructive  features  of  the  work. 
Nor  is  there  any  reason  why  inexact  results,  within  certain 


1  Their  use  is  recommended  by  the  Sub-Committee  of  the  Committee 
of  Ten,  by  the  Committee  of  Nine,  by  the  Committee  on  College  Entrance 
Requirements,  and,  most  recently,  by  the  College   Examination  Board 
of  the  Middle  States  and  Maryland. 

2  The  whole  subject  of  quantitative  experiments  is  admirably  treated 
by  Dr.  Newell  in  SCHOOL  SCIENCE  (see  References). 


INSTRUCTION  IN  THE  LABORATORY       115 

limits,  should  fail  to  point  to  a  law  expressed  in  mathematically 
exact  terms. 

It  is  instructive  to  notice  that  most  of  the  laws  of  chemistry 
were  accepted  long  before  they  were  confirmed  by  work  show- 
ing any  degree  of  exactness.  Black  {Experiments  upon  Mag- 
nesia Alba?-  1782),  for  example,  converted  120  grains  of  chalk 
into  quicklime  and  from  this  recovered  1 18  grains  of  the  original 
material,  showing  an  error  of  1.6  per  cent.  Lavoisier  decom- 
posed mercuric  oxide  and  ascertained  the  weight  of  the  mer- 
cury and  oxygen  formed.  The  error  appears  to  have  been 
about  one  per  cent,  yet  these  results  were  held  to  furnish 
support  to  the  law  of  conservation  of  mass.  Proust  ultimately 
triumphed  in  his  controversy  with  Berthollet,  although  his  own 
measurements  of  definite  proportions  showed  errors  varying 
from  .5  to  5.5  per  cent.  The  law  of  equivalent  proportions 
was  supported  by  Dalton  by  data  which,  in  the  light  of  modern 
work,  are  seen  to  be  affected  by  inaccuracies  sometimes  amount- 
ing to  15  per  cent.  Dalton  {New  Chemical  Philosophy,  318) 
quoted,  in  support  of  the  law  of  multiple  proportions,  values 
for  the  ratios  of  nitrogen  to  oxygen  in  two  oxides  of  nitrogen 
which  show  an  error  of  8  per  cent.2 

The  ideal  of  quantitative  work  for  beginners  is  i  per  cent 
accuracy.  That  this  may  easily  be  attained  with  suitable  ex- 
periments, may  be  seen  from  the  actual  results  of  pupils'  work 
in  many  schools  where  they  are  used.8 

b.  Equipment  for  Quantitative  Experiments  :  —  No  elaborate 
equipment  is  needed  for  these  experiments.  Usually  the  same 
pieces  of  apparatus  which  are  used  in  ordinary  work  will  serve 
for  them.  The  few  special  articles  required  may  each  be 
employed  in  several  if  not  all  of  the  experiments.  A  sufficient 


1  Alembic  Club  Reprints,  No.  i.     Edinburgh,  W.  F.  Clay.     Easton,  Pa. 
Chemical  Publishing  Co.     P.  29. 

2  This  subject  is  discussed  in  detail  by  Vaughan  Cornish.     Practical 
Proofs  of  Chemical  Laws,  \  5,  26,  43,  68,  79. 

3  Sample  results  are  given  by  Newell  in   SCHOOL   SCIENCE,  I.  16, 
and  on  his  Teachers'  Supplement,  13, 14,  17,  etc.,  and  by  Benton,  SCHOOL 
SCIENCE,  I.  148. 


Il6        INSTRUCTION  IN  THE  LABORATORY 

equipment  for  a  large  class  does  not  imply  that  each  mem- 
ber should  be  furnished  with  a  complete  outfit,  since  all  need 
not  do  the  same  or  any  quantitative  experiment  at  the  same 
time. 

The  chief  item  is  the  balance.     Using  an  expensive  instru- 
ment, however,  is  not   only  unnecessary,  but  wasteful.     A  bal- 
ance with   case,    such  as  Becker  No.   31,   costing 
The  Balance. 

$15,  and  sensitive  to  one  centigram,  will  serve  all 

purposes.  A  set  of  weights  (50  gr.  —  i  cgm.),  costing  in  a 
box  $1.50,  will  also  be  needed.  Newell  {Experimental  Chemis- 
try, 347)  describes  a  mode  of  enclosing  common  horn-pan 
scales,  costing  originally  $1.25  to  $2.25,  which  makes  them 
applicable  in  this '  work,  and  other  teachers  confirm  this 
statement. 

One  source  of  trouble  lies  in  the  rusting  of  the  balance.  This 
is  reduced  to  a  minimum  in  a  form  of  the  instrument  which 
is  manufactured  entirely  of  aluminium  and  glass/  and  is  rec- 
ommended and  figured  by  Benton  (SCHOOL  SCIENCE,  I. 
148).  Another  source  of  annoyance  is  the  continual  loss  of 
the  smaller  weights.  This  becomes  impossible  with  the  use  of 
the  Chaslyn  balance,2  figured  on  the  back  of  the  same  number 
of  SCHOOL  SCIENCE  (May  ist,  1901),  in  which  rings  which  can- 
not be  removed  from  the  apparatus  take  the  place  of  weights. 
I  have  found  this  balance  very  satisfactory. 

The  only  other  more  or  less  special  pieces  of  apparatus  re- 
quired are  burettes  (graduated,  and  holding  50  c.c.),  porcelain 

crucibles  (No.  o),  porcelain  boats,  large  bottles 
Apparatus.  (one  ntre  bottles,  or  five-pint  mineral-water  bottles), 

a  barometer,  and  thermometers.  Rubber  stoppers 
save  the  loss  of  much  time,  and  indeed  are  in  the  end  cheaper 
than  corks.  Platinum  ware  is  never  needed,  but  clean  crucible 
tongs  will  be  found  useful. 

1  Made  by  The  Crowell  Apparatus  Co.,  Indianapolis. 

2  Made  by  The  Chicago  Laboratory  Supply  and  Scale  Co.     Another 
form,  "the  triple  beam  balance,"  sensitive  to  8  mgm.,  is  made  by  the 
Apfel-Murdock   Co.  (82   Lake   St.,  Chicago).     A  similar  instrument  is 
sold  by  Richards  &  Co.  also. 


INSTRUCTION  IN  THE  LABORATORY        1 1/ 

c.  Suitable  Quantitative  Experiments:  —  So  many  of  these 
have  been  employed  in  recent  text-books  and  laboratory  manuals 
that  detailed  description  is  unnecessary.  We  may  Quantitative 
refer  to  a  few  which  have  been  tried  and  found  Experiments, 
trustworthy.  They  are  arranged  according  to  the  subjects  in 
connection  with  which  they  are  used. 

Definite  Proportions :  —  Action  of  hydrochloric  acid  on  varying 
quantities  of  ammonium  hydroxide  or  sodium  carbonate  (A. 
Smith/  8). 

Combining  Weights :  —  By  direct  union  of  copper  and  oxygen, 
or  direct  formation  of  cuprous  sulphide  (Tilden,  15).  In- 
directly by  action  of  nitric  acid  on  copper,  zinc,  iron,  tin,  or  mag- 
nesium, and  ignition  leaving  the  oxide  (Tilden,  14;  A.  Smith, 
18).  Indirectly  by  union  of  iodine  and  magnesium  and  for- 
mation of  the  oxide  by  ignition  of  the  iodide  (Young,2  34). 
By  decomposition,  mercuric  oxide  (Nevvth,3  105),  silver 
oxide  (Ramsay,4  97).  The  composition  of  water  is  some- 
what difficult  to  measure  on  account  of  the  small  weight  of  the 
hydrogen  (Newell,5  97  ;  Tilden,  34  ;  Perkin  &  Lean,  286). 

Hydrogen  Equivalents :  —  By  measuring  the  volume  of  hydro- 
gen displaced  by  zinc,  magnesium,  aluminium,  sodium,  etc. 
(Remsen,6  47;  A.  Smith,  19;  Perkin  &  Lean,  204;  Torrey,7 
147).  By  measuring  the  weight  of  the  hydrogen  lost  (Perkin  & 
Lean,  206 ;  Reynolds,8  23). 

Inter-Equivalents  of  Metals :  —  Zinc  and  copper  (Cornish, 
91),  zinc  and  silver  (Newth,  140),  magnesium  and  silver 


1  The  names  in  parenthesis  in  this  section  refer  to  books  listed  in  the 
Bibliography  or  described  already  in  other  connections. 

2  A.  V.  E.  Young.     Elementary  Principles  of  Chemistry.     Part  II. 

3  Newth.     Elementary  Inorganic  Chemistry. 

4  Ramsay.     Experimental  Proofs  of  Chemical  Theory. 

5  Lyman  C.  Newell.     Experimental  Chemistry. 

6  Remsen  &  Randall.     Chemical  Experiments.      New  York,  Henry 
Holt  &  Co.     1895. 

7  James  Torrey.     Studies  in  Chemistry. 

8  J.  E.  Reynolds.     Experimental   Chemistry.     Part   I.     London   and 
New  York,  Longmans,  Green  &  Co.     1897  (7th  ed.). 


Il8        INSTRUCTION  IN   THE  LABORATORY 

(Reynolds,  17),  iron  and  copper,  magnesium  and  silver  (Per- 
kin  &  Lean,  302  and  305). 

Multiple  Proportions:  —  Reduction  of  cupric  and  cuprous 
oxides  (A.  Smith,  17).  Reduction  of  nitrous  and  nitric  oxides 
and  collection  of  the  nitrogen  (Ramsay,  82-86).  The  reduc- 
tion of  lead  monoxide  and  dioxide  will  be  found  suitable  if  the 
pure  substances  can  be  obtained.  Note  that  the  former  takes 
up  carbon  dioxide  from  the  air.  The  monoxide  is  difficult  to 
reduce.1 

Solubility  of  Salts :  — Measurement  at  different  temperatures 
(Richardson,  9). 

Raoulfs  Laws :  —  Depression  of  freezing  point  and  elevation 
of  boiling  point  of  solutions  (Young,  Part  II.,  54-57). 

Gas  Density :  —  Several  excellent  methods  are  described  by 
Professor  Ramsay  (Ibid.,  26,  34,  39,  45).  These  have  been 
borrowed  freely,  and  many  of  them  will  be  found  in  the  other 
books  we  have  quoted.  Another  method,  that  of  Regnault 
(Perkin  &  Lean,  234),  gives  good  results. 

Volumetric :  —  This  takes  the  form  usually  of  titration  of  solu- 
tions of  acids  and  bases.  Volumetric  experiments  with  gases, 
illustrating  Gay  Lussac's  law,  we  owe  chiefly  to  Hofmann. 
These  are  concerned  with  the  volumetric  composition  of  steam, 
ammonia,  and  hydrogen  chloride ;  they  are  described  in  many 
works.  The  combination  of  oxygen  and  nitric  oxide  (Tilden, 
252;  Young,  40),  the  volumetric  composition  of  nitric  oxide 
(Tilden,  25 1)  of  ammonia  (Ramsay,  59),  and  of  the  air  (Cooley,2 
61)  will  be  found  useful. 

Special ':  —  A  very  instructive  experiment,  in  which  a  weighed 
amount  of  silver  foil  is  converted  first  into  the  nitrate,  then  into 
the  oxide,  and  finally  back  to  silver,  is  used  by  Benton 
(SCHOOL  SCIENCE,  I.,  157).  It  has  the  advantage  of  enabling 
the  pupil  to  check  his  result,  since  the  silver  is  weighed  at  the 


1  Other  instructive  illustrations  are  given  by  Young  (Ibid.,  Part  II., 
30),  W.  R.  Smith  (SCHOOL  SCIENCE,  I.,  87),  A.  Smith.  18. 

2  Le  Roy  C.  Cooley.     Laboratory  Studies  in  Elementary  Chemistry. 
New  York,  American  Book  Co.     1894. 


INSTRUCTION  IN  THE  LABORATORY        119 

beginning  and  end.  The  reduction  of  silver  nitrate  by  hydro- 
gen (Cornish,  34),  measurement  of  water  in  hydrates  ('  water 
of  crystallization/  A.  Smith,  21),  and  the  proportion  of  the 
carbon  dioxide  in  a  carbonate  (Newth,  228;  Newell,  215) 
will  also  be  found  applicable.  The  determination  of  the  com- 
position of  zinc  chloride  (Torrey,  140),  when  taken  in  con- 
nection with  the  measurement  of  the  hydrogen  equivalent  of 
zinc,  permits  a  complete  investigation  of  the  action  of  zinc  on 
hydrochloric  acid  to  be  made. 

d.  The  Application  of  Quantitative  Experiments :  —  There  is 
one  danger  to  which  the  use  of  exact  measurement  is  liable, 
and  that  is,  that  the  pupil  may  be  misled  into  thinking  that  the 
operation  of  measurement  is  an  end  in  itself.  The  scientific 
mechanic  who  cannot  see  beyond  the  cross  wires  of  a  telescope 
is  not  the  person  we  are  trying  to  train.  Measurement  is  a  tool 
and  should  be  used,  aside  from  a  preliminary  exercise  or  so, 
only  in  the  solution  of  some  definite  problem.  As  Professor 
Perkin 1  says,  "  measurements  should,  in  fact,  be  made  only  in 
reference  to  some  actual  problem  which  appears  to  be  really 
worth  solving,  not  in  the  accumulation  of  aimless  details."  It 
is  in  this  respect  that  these  experiments  resemble  investigation 
rather  than  quantitative  analysis. 

The  time  at  which  the  first  quantitative  experiment  may  be 
given  naturally  depends  upon  many  things,  particularly  the  pre- 
vious experience  of  the  pupil.  Some  practice  in  Time  of  j^,,. 
ordinary  chemical  work  will  be  needed  by  way  of  duction' 
preparation.  The  experiments  should  be  used,  however,  not  later 
than  the  laws  which  they  illustrate,  and  measurements  of  com- 
bining weights  must  certainly  be  introduced  before  equations 
are  used.  To  leave  them  to  the  end  of  the  course  is  practically 
to  postpone  them  until  they  become  superfluous.  Their  early 
introduction  is  particularly  desirable,  in  order  that  the  pupil,  in 
spite  of  the  laws  he  may  have  learned,  may  not  acquire  from 

1  Vice-Presidential  address  already  mentioned.  See  on  this  point 
Picton,  The  Great  Shibboleth  (  SCHOOL  WORLD,  October  and  November, 
1899),  and  also  Lean  (Ibid.,  II.  (1900),  78). 


120        INSTRUCTION  IN  THE   LABORATORY 

his  practical  experience  the  impression  that  chemical  propor- 
tions are  after  all  purely  matters  of  chance.  The  teacher  can 
only  find  out  by  trial  the  earliest  point  at  which,  with  his  par- 
ticular class,  they  may  be  introduced. 

When  obviously  inexact  results  are  presented,  they  should 
never  be  dismissed  abruptly  and  with  contempt.^  Sometimes  a 

Treatment  of  discussion  of  these  very  results,  and  how  he  got 
Poor  Results.  ^Qm>  wjtn  tne  pupil,  wjn  teach  more  t}ian  jf 

they  had  turned  out  well,  and  had  been  accepted  without  criti- 
cism. \  The  fact  must  be  continually  impressed  on  the  mind  of 
the  pupil  that  it  is  the  conscientious  performance  of  the  experi- 
ment that  is  wanted,  and  not  a  certain  result.)  If  the  reverse 
impression  is  given,  the  pupil  may  resort  to  '  cooking '  his 
figures,  and  the  exercise  may  do  harm  instead  of  good.  The 
teacher  should  always  ascertain  for  himself,  by  trial  with  the 
same  apparatus,  the  limits  within  which  results  may  be  accepted 
as  representing  good  work. 

In  all  cases  the  pupil  should  be  warned  not  to  throw  away 
the  product,  in  case  the  result  seems  to  be  bad,  until  he  has  sub- 
mitted it  to  the  teacher.  Sometimes  the  result  may  be  corrected, 
and  repetition  of  the  experiment  be  avoided,  as  when  through 
misunderstanding  the  pupil  gets  a  result,  correct,  but  different 
from  that  which  he  had  expected  ;  when  the  product  has  been 
insufficiently  dried ;  or  when  some  arithmetical  error  has  been 
made  in  the  calculation.  Pupils  rarely  feel  any  reluctance  to 
repeat  experiments  of  this  kind,  a  fact  which  in  itself  testifies 
strougly  to  the  interest  they  feel  in  them. 

e.  Benefits  and  Objections :  —  The  general  benefits  which 
these  experiments  confer  scarcely  need  enumeration.  They 

teach  the   necessity  for  care,  exactness,  patience, 
Benefits.  J 

and  cleanliness,  by  themselves  demonstrating   too 

often  the  effects  of  lack  of  application  of  these  elementary 
virtues.  They  give  the  pupil  a  confidence  in  the  exactness  of 
the  experimental  basis  on  which  the  science  rests,  and  a  respect 
for  exact  experimental  work,  which  he  could  not  otherwise  at- 
tain. They  take  time,  but  their  very  slowness  is  in  some  ways 


INSTRUCTION  IN   THE   LABORATORY       121 

an  advantage.  The  laboratory  should  be  a  place  for  thinking 
as  well  as  for  seeing.  I  have  found  that  questions  often  suggest 
themselves  to  the  minds  of  the  pupil  during  the  leisure  which 
some  stages  of  these  experiments  permit,  the  effort  to  answer 
which  teaches  them  much  they  might  not  have  otherwise 
learned.  The  arithmetical  problems  arising  out  of  these  ex- 
periments, founded  as  they  are  on  their  own  data,  are  worked 
by  the  pupils  with  an  amount  of  interest,  not  to  say  eagerness, 
which  artificially  made  problems  can  never  inspire. 

Some  of  the  objections  l  which  have  been  urged  against  their 
use  have  already  been  noticed  incidentally.      The   statement 

that    high    school    pupils   lack   skill    to    carry   out 

3  Objections. 

these  experiments  is  either  a  commentary  on  the 

selection  which  the  teacher  has  made,  or  a  piece  of  rather  ob- 
scure humour.  It  is  in  the  effort  to  gain  skill  which  they  call 
forth  that  part  of  their  value  lies.  The  argument  that  in  colleges 
quantitative  analysis  usually  does  not  appear  until  the  third  year, 
and  that  quantitative  experiments  are  not  given  in  general  chem- 
istry, may  be  a  criticism  of  college  teaching,  but  it  is  not  an 
argument  against  the  use  of  these  experiments.  Finally,  the 
suggestion  that  historically  chemistry  was  qualitative  before  it 
was  quantitative,  and  that  the  historical  order  should  be  fol- 
lowed, seems  to  misapply  an  important  principle.  The  history 
of  modern  chemistry  begins  with  Priestley,  Lavoisier,  and  Cav- 
endish, but  it  was  the  quantitative  part  of  their  work  which 
alone  really  deserved  the  designation  fundamental.  It  is  diffi- 
cult to  see  why  a  pupil  should  be  dragged  through  a  fog- 
bank  of  alchemy  and  empiricism  simply  because  the  rest  of 
the  world  lost  its  way  and  wandered  in  such  a  fog  for  hundreds 
of  years. 


1  An  extended  treatment  of  a  long  list  of  objections,  including  all  that 
have  been  urged  with  the  exception  of  two,  is  given  by  R.  P.  Williams, 
New  England  Society  of  Chemistry  Teachers,  Report  of  the  Fifth  Meeting, 
3-6.  Some  of  the  arguments  in  their  favour  are  well  put  by  Young, 
Suggestions  to  Teachers,  designed  to  accompany  his  Elementary  Principles 
of  Chemistry^  2-4. 


122        INSTRUCTION  IN   THE  LABORATORY 

VII.     The  Role  of  the  Teacher  in  the  Laboratory. 

One  of  the  most  serious  faults  of  much  chemistry  teaching  is 
that  the  pupils  are  allowed  to  work  by  themselves  in  the  labo- 
ratory in  the  absence  of  the  teacher.  \  None  of  the 

Continuous      benefits  we  have  enumerated  above,  or   of  the  re- 
Attendance 
in  the  suits  anticipated     from  the  methods  of  laboratory 

ory'  instruction  just  described,  can  possibly  be  realized 
in  the  smallest  degree  when  this  course  is  pursued.  The  pupils 
cannot  be  expected  to  teach  themselves  chemistry  any  more 
than  they  could  give  themselves  instruction  of  the  slightest 
value  in  Latin  or  mathematics  under  the  same  circumstances. 
The  Latin  room  cannot  teach  Latin,  and  the  chemical  labora- 
tory is  not  more  fit  than  any  other  apartment  to  take  the  place 
of  the  instructor.  The  natural  result  of  neglect  of  continuous 
and  strenuous  supervision  is  that  the  pupils  think  that  the  per- 
formance of  prescribed  mechanical  operations  constitutes  a  study 
of  chemistry.  This  tendency  of  all  laboratory  work  is  exceed- 
ingly difficult  to  combat,  and  continual  questioning  by  the 
teacher  can  alone  keep  the  work  on  the  level  of  an  intellectual 
exercise.  No  laboratory  outline,  however,  carefully  prepared, 
can  take  the  place  of  the  living  teacher.  His  questions  are 
directed  to  the  particular  features  of  the  particular  way  of  doing 
each  experiment  and  to  the  particular  misconceptions  or  short- 
comings of  each  pupil.  No  two  cases  are  ever  precisely  alike, 
and  therefore  no  printed  questions  can  ever  meet  the  difficulty. 
The  disastrous  blunder  of  permitting  or  encouraging  unsuper- 
vised  work  seems  to  be  commoner  in  colleges  than  in  secondary 
schools.  But,  until  it  is  recognised  and  remedied,  we  can 
never  secure  either  culture  or  a  knowledge  of  chemistry,  either 
for  the  ordinary  student  or  the  prospective  specialist,  merely  by 
including  of  the  science  in  our  curricula. 

Chemical  manipulation  is  an  art.  It  cannot  be  acquired 
without  models  to  copy  and  trenchant  criticism  as  the  work 
proceeds.  The  latter  must  be  applied  the  moment  occasion  for 
it  arises,  or  hours  may  be  wasted  in  trifling  with  unimportant 


INSTRUCTION  IN  THE  LABORATORY        123 

features  of  an  experiment,  or  in  using  an  imperfect  or  inade- 
quate piece  of  apparatus.     Supervision  of  the  technique  is  as 
necessary  in  chemistry  as  in  drawing  or  shopwork. )  Teaching 
Some  pupils  seem  naturally  to  possess  the  '  knack '   Technique. 
of  working  neatly  and   successfully  with  little    assistance,  but 
these  are  very  few  in  number.     The  great  majority  are  utterly 
incapable  of  giving  concrete  expression  to  the  directions  with- 
out frequent  suggestions  and  warnings. 

At   the  beginning,  one  teacher   cannot  handle   successfully 
more  than  fifteen   students.     The  more  the  number  assigned 
to  him  exceeds  this,  the  less  thorough  the  instruc-  j^    f 
tion  and  the  longer  the  time  taken  in  reaching  the  instructors 
same  degree  of  proficiency  must  be.     When  once  topup  s> 
a  good  start  has  been  made,  equally  efficient  work  may  be  done 
with  a  larger  proportion   of  pupils  to  each  instructor.     If  a 
sufficient  force  of  instructors  is  not  available,  the  work  can  be 
simplified  and  more  time  can  be  taken  in  covering  the  same 
ground. 

VIII.    The  Note-book. 
REFERENCES. 

Arey,  A.  L.  A  Paper  on  the  Management  of  Laboratory  Classes  in 
Chemistry,  and  the  discussion  following  its  reading.  Albany,  N.  Y.,  The 
University  of  the  State  of  New  York.  High  School  Bulletin  No.  7  ( 1900), 
678-684.  This  covers  almost  all  phases  of  the  subject. 

Cooke,  J.  P.     Laboratory  Practice.     Pp.  6-8. 

Keeping  a  note-book  is  a  valuable  aid  in  laboratory  study. 
The  notes  should  be  provided  with  prominent  headings  indicat- 
ing the  part  of  the  subject  which  is  being  studied 
and  the  Object  of  each  experiment.     Following  this 
should  appear  a  statement  of  what  was  done,  including  the  mate- 
rials used,  a  description  of  the  apparatus  (with  a  sketch,  if  it  seems 
called  for),  and  the  procedure  adopted.     When  all  this  is  de- 
tailed in  the  laboratory  directions,  however,  it  does  not  seem 
necessary  that  it  should  be  repeated,  unless  perhaps  in  an  ab- 
breviated form.     Next,  the  observations  which  have  been  made 


124        INSTRUCTION  IN   THE  LABORATORY 

should  be  stated,  then  the  inferences  drawn  from  these,  and  in 
most  cases  the  chemical  equations  representing  the  changes 
should  be  given. 

Care  should  be  taken  in  regard  to  the  form  in  which  the 

notes  are  presented,  but  the  lavishing  of  too  much  time  upon 

the  unnecessary  copying  and  beautifying  should  be 

discouraged.     The  use  of  concise  yet  clear  English 

should  be  imperatively  demanded.     But  a  too  formal  division 

of  the  notes  into  columns  containing  "  requirements,  conditions, 

observations,  conclusions,"  is  not  sufficiently  elastic,  represses 

the  individuality  of  the  student,  cultivates  a  mechanical  view  of 

the  subject,  and  should  be  avoided. 

(  The  majority  of  teachers  favour  the  writing  up  of  the  notes  in 
final  form  in  the  laboratory  rather  than  at  home.  This  is  un- 
doubtedly the  better  method.  Inasmuch  as  attainment  of  the 
best  form  cannot  be  reached  in  this  way  at  once,  it  is  well  to  use 
the  even  folios  of  the  book  for  memoranda  and  ciphering,  and 
to  write  the  notes  in  more  formal  fashion  on  the  odd  folios 
opposite,  and  to  do  this  immediately  after  the  experiment  has 
been  performed. 

It  is  indispensable  to  the  success  of  the  system  that  the  note- 
book should  be  examined  periodically  by  the  teacher,  and  all 
Examination  blunders  in  English,  errors  in  observation  and  mis- 
of  Note-books  takes  in  chemistry  marked  distinctly.  The  correc- 
tions themselves,  however,  should  by  no  means  be 
made  by  the  teacher.  In  discovering  the  truth  and  making  the 
necessary  change  himself,  the  attention  of  the  pupil  is  called  to 
the  matter  much  more  forcibly.  The  note-book  should  be  ex- 
amined immediately  after  the  first  exercises,  in  order  that  by 
criticism  and  suggestion  the  best  way  of  making  the  notes  may 
be  most  quickly  communicated.  Later  they  should  be  examined 
at  regular  intervals.  Some  teachers  require  that  the  note-books 
be  left  in  the  laboratory  at  all  times,  and  provide  a  shelf  near 
the  door  on  which  they  may  be  filed  as  the  pupils  pass  out. 
They  are  thus  available  for  examination  during  any  moments  of 
leisure  which  the  teacher  may  find. 


INSTRUCTION  IN  THE  LABORATORY       12$ 

The  reading  of  note-books  when  the  class  is  large  is  the  most 
laborious  and  least  attractive  task  of  the  teacher.  Indeed,  in 
many  cases,  systematic  examination  of  all  the  books  by  one  per- 
son is  impossible  without  assistance.  Sometimes  a  classroom 
hour  may  be  devoted  to  the  reading  of  notes  by  some  of  the 
pupils  and  criticism  by  the  other  members  of  the  class.  Often 
former  pupils  may  be  induced  to  take  a  share  in  the  work.  In 
Normal  Schools,  in  fact,  the  students  will  receive  distinct  benefit 
from  an  opportunity  to  assist,  to  some  small  extent,  in  the  in- 
struction by  examining  note-books  and  taking  part  in  the  super- 
vision of  the  laboratory  work. 

The  extreme  value  of  keeping  a  note-book  in  a  suitable  style 
cannot  be  doubted.  It  impresses  the  facts  ten  times  more 
strongly  on  the  memory  than  would  be  the  case  value  of  the 
without  its  use.  It  gives  practice  in  accurate  and  N°te-l>ook. 
clear  expression.  As  an  incident  to  the  writing,  the  pupil  usu- 
ally finds  his  thoughts  on  the  subject  were  not  so  perfectly 
organized  as  he  had  supposed.  In  framing  written  answers  to 
the  interrogation  points  and  questions  in  the  directions,  he  is 
stimulated  to  group  the  facts  in  new  ways,  and  is  assisted  in 
studying  the  subject  by  the  discovery  of  gaps  in  his  thought  and 
in  his  observation  which  otherwise  would  have  passed  unnoticed. 
If  the  note-making  is  to  be  perfunctory,  it  had  better  not  be 
attempted  at  all,  for,  instead  of  yielding  the  benefits  we  have 
mentioned,  it  will  simply  waste  the  time  of  both  pupil  and 
teacher. 

IX.     Emergencies. 

Guarding  the  pupils  from  injury  by  specific  laboratory  direc- 
tions,1 due  and  pointed  warning,  and  continuous  oversight  is  one 
of  the  most  serious  responsibilities  of  the  teacher  of  p^ger  from 
chemistry.     When,  in  spite  of  this,  slight  accidents   Injuries, 
occur,  as  they  frequently  do,  he  must  be  prepared  to  treat  the 

1  As  prevention  is  better  than  cure,  the  pupils  should  be  positively 
forbidden  to  make  any  experiments  of  their  own  devising  without  first 
consulting  the  teacher. 


126        INSTRUCTION  IN   THE  LABORATORY 

injury  properly.  Aside  from  damage  to  the  eyes,  burns  are  the 
most  serious  injuries  with  which  he  is  called  upon  to  deal.  They 
are  to  be  regarded  very  seriously,  because,  through  the  destruc- 
tion of  the  protective  power  of  the  skin,  infection  will  almost 
always  occur  unless  the  burn  is  very  small  indeed.  This  will  be 
followed  by  suppuration,  and  the  resulting  wound  will  leave  an 
exceedingly  ugly  scar.  In  such  cases,  therefore,  careful  disin- 
fection should  never  be  omitted. 

Burns  through  contact  with  hot  bodies,  or  from  burning  liquids 
like  alcohol,  should  be  treated  first  with  an  emulsion  of  linseed 
oil  and  lime  water.  Burns  produced  by  corrosive 
liquids  like  bromine,  sulphuric  acid,  and  nitric  acid 
should  be  washed  with  water,  and  then  the  part  should  be 
rubbed  gently  with  a  paste  made  of  sodium  bicarbonate  and  a 
little  water  (the  normal  carbonate  is  alkaline  and,  having  an 
irritating  effect,  should  not  be  used).  In  all  these  cases,  to  pre- 
vent infection,  carbolated  vaseline  or  powdered  boracic  acid 
should  be  applied  liberally  to  every  part  of  the  surface  burned, 
and  a  bandage  should  then  be  wound  around  the  whole.  A 
"  wet  dressing  "  is  often  used.  Saturated  boracic  acid  solution, 
(i  :  20)  diluted  with  an  equal  volume  of  water,  is  employed. 
The  piece  of  lint,  large  enough  to  extend  some  distance  beyond 
the  burn  in  every  direction,  is  soaked  with  this  solution,  and  cov- 
ered with  a  sheet  of  oiled  silk  or  "  protective"  to  restrain  evap- 
oration. Burns  caused  by  phosphorus  are  the  most  difficult  to 
heal.  They  should  be  first  cleansed  by  washing  with  a  brush 
dipped  in  water  containing  a  little  carbolic  acid.  If  necessary 
carbon  disulphide  may  be  applied.  The  best  results  seem  to  be 
obtained  when  the  wound  is  then  powdered  over  with  picric 
acid  and  wrapped  in  a  wet  bandage.  When  the  injury  includes 
the  contact  of  acid  with  the  eyes,  washing  with  water  and  a  solu- 
tion of  sodium  bicarbonate  projected  from  a  wash  bottle  should 
be  applied,  and  the  victim  of  the  accident  sent  at  once  to  a  com- 
petent physician. 

Cuts  should  be  washed  out  with  water,  and,  after  certainty  has 
been  reached  that  any  glass  they  may  contain  has  been  removed, 


INSTRUCTION  IN  THE  LABORATORY        1 27 

they  should  be  covered  with  court-plaster.  A  solution  of  '  iron 
persulphate,'  or,  in  an  emergency,  ferric  chloride  will  arrest 
bleeding.  If  the  cut  is  otherwise  than  small,  a  dis- 
infectant will  be  required.  A  dry  mixture  of  sali- 
cylic acid,  one  part,  and  boracic  acid,  two  parts,  applied  liberally 
and  held  in  place  by  a  bandage,  is  a  suitable  dressing.  In  case 
of  faintness,  inhalation  of  ammonium  hydroxide,  or  administra- 
tion of  five  drops  of  ammonium  hydroxide  in  a  little  water  will 
usually  be  effective.  The  irritation  caused  by  inhaling  acid 
fumes  will  be  relieved  by  inhalation  of  ammonia,  and  that  from 
chlorine  and  bromine  by  the  inhalation  of  vapour  of  alcohol. 

Fires  caused  by  burning  liquids  like  carbon  disulphide  are  not 
affected  by  water,  and  should  be  put  out  by  liberal  use  of 

sand.     Burning  clothing  can  be  extinguished  best 

.  r  Fires. 

by  means  of  a  wet  towel. 

The  various  materials  mentioned  above,  along  with  a  pair  of 
scissors,  should  be  kept  on  hand  in  some  special  cupboard,  in  a 
conveniently  accessible  position,  and  they  should  never  be  used 
for  any  other  purpose  than  that  for  which  they  are  intended. 


CHAPTER  V 

INSTRUCTION    IN   THE    CLASSROOM 

IN  order  that  the  purposes  which  we  have  so  far  explicitly 
discussed,  or  implicitly  assumed,  may  be  realized,  several  dis- 
tinct means  of  instruction  are  at  the  disposal  of  the.  teacher 
and  should  all  be  used.  Of  these  the  individual  laboratory  ex- 
perience of  the  pupils  is  the  most  important.  The  utilization 
of  this  experience,  however,  will  never  occur  spontaneously. 
The  results  will  remain  largely  incoherent  and  meaningless 
without  discussions,  —  ' quizzes'  —  in  which  they  are  infused 
with  life,  experimental  demonstrations  in  which  they  are  am- 
plified, problem-working  in  which  they  are  made  more  definite 
and  are  driven  home,  and  book  study  and  reference  work  in 
which  they  are  brought  into  relation  with  the  rest  of  the 
science. 

a.  Oral  and  Written  Quizzes:  —  The  oral  quiz  naturally 
follows  the  laboratory  work  and  deals  mainly  with  this,  because 
The  Services  ^  *s  ^ie  notm§  °f  tne  significant  facts  and  their 
Rendered  by  translation  into  chemical  knowledge  which  gives 
t  e^  "  most  difficulty  to  the  beginner.  It  will  draw  out 
much  that  was  unheeded  at  the  time,  but  remains  accessible  to. 
careful  questioning,  and  so  will  prepare  the  way  for  more  adequate 
observation  in  the  future.  It  will  also  relate  this  work  to  the 
statements  of  the  book  and  keep  the  two  from  remaining  two 
different  things,  as  they  have  a  tendency  to  do.  Through 
criticism  of  loose  expressions,  by  the  teacher  and  by  other 
members  of  the  class,  it  will  bring  out  lack  of  clearness  of 
thought  and  at  the  same  time  teach  discrimination  in  the  use 
of  language. 

Aside   from   these,  there  are  assigned  to  it  three  services 
which  would  remain  entirely  unrendered  if  the  quiz  did  not 


INSTRUCTION  IN   THE   CLASSROOM          129 

undertake  them.  ^One  is  that  of  developing  the  generalizations 
of  the  science  from  the  facts,  of  which  those  observed  in  the 
laboratory  are  samples.  Thus  the  pupil  may  have  treated  zinc 
with  half-a-dozen  acids,  yet  will  almost  never  even  speculate  on 
the  probable  generalization  unaided.  The  second  service  is  in 
practising  the  application  of  the  generalizations  to  chemical 
questions  and,  when  possible,  to  those  of  every  day-life.  Gen- 
eralizations are  the  tools  of  thought,  and  unless  they  are  put  to 
some  use  the  labour  involved  in  their  manufacture  will  have 
been  largely  wasted.  The  third  service  is  in  exercise  of  the 
scientific  imagination,  without  which  attainment  of  even  the 
slightest  degree  of  chemical  intelligence  is  impossible.  This 
furnishes  one  form  of  the  so-called  'explanations'  (cf.  p.  147) 
which,  when  legitimately  used,  are  so  helpful. 

To  sum  up,  the  object  of  the  quiz  is  to  lead  the  pupil  to  gain 
the  scientific  habit  of  mind  by  practice  in  the  scientific  treat- 
ment of  a  specific  science. 

Of  these  features  of  the  quiz,  only  the  two  last  seem  to 
demand  special  discussion. 

When  a  generalization  has  been  stated  it  will  find  immediate 
application.  Frequently  some  little  time  will  have  to  be  de- 
voted to  making  the  application  plain.  For  ex- 

_     .      Service  in 
ample,  the   law   of   conservation   of  matter   finds   showing  Ap- 

illustration  in  the  results  of  raising  the  same  crop  plication  of 
,  -  ,       ,  ..  ,f   .       Conclusions, 

on  the  same  |)i£ee~of  midyear  after  year.     If  the 

product  is  one  which  is  cut  and  carried  off  entirely,  the  constit- 
uents of  the  soil  which  are  essential  parts  of  the  food  of  the  plant 
are  effectually  removed.  Analysis  of  the  soil  and  of  the  plant 
show  at  once  what  stock  of  plant  food  is  available,  and  how  long 
it  will  last.  The  use  of  fertilizers  and  other  expedients  replaces 
or  brings  within  reach  of  the  plant  the  phosphates,  for  example, 
which  are  indispensable  to  its  growth.  If  it  is  the  law  of  de- 
finite proportions  which  is  under  discussion,  illustrations  are 
abundant.  In  its  absence  we  could  not  regulate  the  heating  of 
our  houses,  because  with  the  same  draft  and  supply  of  oxygen 
the  combustion  would  be  more  fierce  at  some  times  than  at 

9 


130         INSTRUCTION  IN  THE   CLASSROOM 

others :  we  could  not  make  a  contract  for  the  supply  of  iron 
because  we  could  not  foretell  what  amount  of  coal  would  be 
required  to  reduce  our  ore,  and  therefore  what  the  expense 
of  producing  the  metal  was  likely  to  be  :  we  could  not  offer 
photographs  at  so  much  a  dozen,  because  the  second  half  of 
the  dozen  might  cost  a  thousand  times  as  much  to  print,  de- 
velop, or  tone  as  the  first.  Commercial  analysis,  by  the  results 
of  which  values  were  to  be  determined,  would  be  made  utterly 
in  vain.  In  fact,  the  conduct  of  all  industries  depending  on 
chemistry  would  be  impossible  as  business  enterprises.  Even 
life  itself  would  cease,  since  its  continuance  depends  on  the 
assumption  that  approximately  constant  quantities  of  food  will 
give  approximately  constant  results  in  the  way  of  nourishment. 
A  little  thought  will  show  that  similar  illustrations  of  almost  all 
the  generalizations  of  chemistry  may  be  found.  Visits  to  fac- 
tories will  usually  furnish  many  opportunities  for  pointing  out 
applications  of  facts  noted  in  the  classroom.1 

By  inference  is  meant  a  rigidly  logical  process  in  which  no 
steps  are  omitted  and  no  gratuitous  or  surreptitious  additions 
Service  in  are  made  to  the  conclusion  to  which  the  data  fairly 
Furnishing  lead.  For  example,  when  hydrogen  chloride  is 
lon'  formed  by  the  action  of  sulphuric  acid  on  salt,  we 
infer  that  under  the  circumstances  the  hydrogen  of  the  acid 
could  unite  with  the  chlorine  and  the  sodium  with  the  sulpha- 
nion  (SO4)  ;  that  is,  that  affinity  between  these  materials  exists. 
We  may  not  infer  that  this  affinity  was  much  greater  than  that 
which  held  the  original  compounds  together,  nor  that  sulphuric 
acid  is  more  active  ('  stronger  ')  than  hydrochloric  acid.2  Nor 
may  we  infer  that  a  tendency  to  the  formation  of  gases  accounts 
for  the  action.  '  Accounting  for '  and  *  explaining  '  chemical 
changes  is  a  risky  proceeding.  It  is  usually  beyond  the  be- 
ginner. In  this  illustration,  a  knowledge  of  mass  action  is 
needed  for  the  purpose.  Supposing  causes  should  never  be 


1  This  subject  is  discussed  farther  in  par.  e,  p.  138. 

2  As  a  matter  of  fact,  both  these  conclusions  would  be  completely 
erroneous. 


INSTRUCTION  IN  THE   CLASSROOM         131 

indulged  in.  Explanations  are  very  satisfying,  but  we  must 
be  careful  to  avoid  incorrect  ones  as  they  are  much  worse  than 
none.  An  illustration  of  the  use  of  the  imagination  will  help  to 
show  how  far  the  attempt  may  safely  go. 

The  imagination  (cf.  p.  n)  must  be  applied  to  everything  in 
chemistry.     For  example,  why  is  the  generation  of  chlorine  such 

a  leisurely  process  ?     It  is  not  for  lack  of  affinity 

. .      .  .  i    Service  in 

that  the  interaction  of  the  manganese  dioxide  and   Employment 

hydrochloric  acid  refuses  to  be  hurried  even  by  a  blast-   of  the  imag- 

J  ...        ination. 

lamp  !     To  answer  the  question,  we  have  to  imagine 

the  whole  affair  in  detail.  The  molecules  of  the  substances  must 
meet  to  act.  The  acid  is  in  solution,  and  from  six  to  twelve 
molecules  of  water  encounter  a  lump  of  dioxide  for  every  one 
of  acid  that  reaches  the  goal.  After  the  one  acts,  another  has 
to  come  up  by  diffusion,  a  slow  process.  Again,  the  dioxide  is 
insoluble  and  does  not  go  to  meet  the  acid.  How  great  is  the 
contrast  between  the  action  of  hydrochloric  acid  on  similar 
pieces  of  marble  and  of  sodium  carbonate  on  this  account. 
The  molecules  of  dioxide  have  to  be  sought,  and  only  the  surface 
ones,  the  merest  infmitesimally  small  fraction  of  the  whole,  are 
within  reach.  Contrast  this  with  the  rapid  action  in  the  '  Seidlitz' 
powder,'  where  both  bodies  are  dissolved.  Then  the  manganous 
chloride  formed  has  to  diffuse  away  to  expose  a  new  surface.  And, 
when  we  try  heating,  we  cannot  raise  the  temperature  much, 
because  aqueous  hydrochloric  acid  boils  at  110°  or  lower. 
Contrast  this  with  our  custom  of  raising  the  temperature  to  a 
red  heat  in  making  oxygen.  Here,  to  avoid  distilling  over 
some  of  the  acid,  and  so  wasting  it  and  rendering  the  chlorine 
impure  at  the  same  time,  we  may  not  go  even  as  high  as  100°. 
It  will  be  noted  that  we  are  not  accounting  for  the  chemical 
action,  or  supposing  causes  for  it.  We  are  simply  considering 
the  details  and  trying  to  explain  how  the  conditions  affect  the 
change.  The  tremendous  role  which  the  imagination  plays  in 
this  hardly  needs  to  be  pointed  out. 

"  Imagination  is  thought  by  means  of  images  "  (Wundt).    It 
gives  new  form  or  grouping  to  the  relations  of  the  contents  of 


132          INSTRUCTION  IN  THE   CLASSROOM 

the  memory  and  the  percepts  of  the  senses.  In  the  above  illus- 
tration it  uses  the  pictorial  imagery  of  the  molecular  theory,  a 
multitude  of  facts,  and  some  ideas  about  molecular  forces  for 
the  production  of  a  rationalized  kinetoscope  picture  of  the 
whole  proceeding. 

The  quiz  will  fitly  occupy  a  large  portion  of  the  whole  time 
near  the  beginning,  when  all  is  new,  and  again  during  the  last 
half  of  the  course.  As  the  subject  advances,  earlier  matters, 
already  partly  forgotten,  receive  fresh  light  from  and  reflect  val- 
uable light  upon  each  successive  topic. 

Some  of  the  objects  of  the  quiz  enumerated  above  will  be\ 
especially  well  served  by  occasional  written  exercises  or  informal 
written  examinations.  These  are  particularly  valuable  inas- 
Exercises.  much  as  they  give  the  pupils  practice  in  making 
connected  statements,  such  as  accounts  of  the  properties  of 
substances  and  extended  discussions  of  chemical  questions, 
and  so  train  them  in  the  chemist's  way  of  classifying  his 
facts  and  expressing  his  conclusions.  They  also  furnish  oc- 
casion for  that  continual  reviewing  which  is  so  indispensable. 

The  nature  of  the  questions  asked  in  a  written  exercise  shows  M 
more  clearly  than  any  other  one  thing  the  kind  of  instructionV 
they  are  testing.     Questions  such  as  :  What  are  the  colours  of 
the  precipitates  when  such  and  such  substances  are  mixed  ?  or/ 
Give  the  graphic,  semi-graphic,  and  empirical  formulae  of  the 
following  substances,  —  are  tests  of  memory  and  show  serious 
misdirection  of  the  pupils'  energy.     The  questions  should  test    'f 
the  powers  of  reasoning,  discrimination,  and  co-ordination,  as     j 
well  as  the  knowledge  of  the  pupil.     They  should   be  con- 
structed so  as  to  demand  reference  to  laboratory  experience 
for  correct  answer. 

For  example,  if  we  ask  what  the  action  of  hydrochloric  acid 
on  quick-lime  is,  the  answer  may  be  given  by  rote.  If  we  ask, 
How  would  you  show  the  presence  of  oxygen  in  quick-lime? 
the  pupil's  thought,  disciplined  by  laboratory  experience,  alone 
can  furnish  the  reply.  The  answer,  "  I  don't  know,"  or  "  I 
don't  remember,"  which  we  often  receive,  is  a  pointed  com- 


INSTRUCTION  IN  THE   CLASSROOM          133 

mentary  on  the  habit  of  mind  our  educational  methods  seem 
to  engender.  The  question  invited  the  pupil  to  think,  and  this 
was  so  unusual  that  he  did  not  even  recognise  the  fact. 

The  Committee  of  Ten   recommended    that   examinations 
should  be  practical  as  well  as  oral  or  written.     They  referred 
to  college  admission  examinations,  but  the  idea  is   practical 
equally  applicable  to  any  test  of  acquirement  what-   Examinations, 
ever  its  purpose.1 

b.  Experimental  Demonstrations :  —  Some  teachers  prefer 
this  work  to  precede,  others  to  succeed  the  laboratory  exercise 
on  the  same  topic.  In  the  latter  case  the  desire  is  to  let  the 
pupil  examine  the  subject  first  entirely  by  his  own  efforts.  This 
is,  doubtless,  as  a  general  rule,  the  best  plan.  But,  while  the 
pupil  is  still  ignorant  of  the  handling  of  apparatus  and  the  kind 
of  phenomena  to  be  expected,  it  must  involve  slow  progress  and 
much  supervision.  After  some  experience  has  been  gained,  it 
is  undoubtedly  more  instructive  as  well  as  more  interesting  than 
the  other  arrangement. 

The  first  of  the  uses  of  the  demonstration  is,  in  connection 
with  the  earlier  exercises,  to  show  simple  experiments,  to  point 
out  the  matters  of  observation  and  to  indicate  the   Usesof  th 
inferences    to    be   drawn.      These  in   fact  will  be   Demonstra- 
model   laboratory   studies,    showing    something   of 
the  nature  and   use   of  the  apparatus,   and  intended   to  save' 
the  pupil  much   needless   bungling  in   his  first   efforts.     The 
experiments  need  not  be  the  same  as  those  performed  in  the 
laboratory.     Yet  even  if  they  are,  the  whole  affair  seems  so 


1  Perkin  and  Lean  give  a  large  number  of  simple  problems  (ibid., 
324-326)  to  be  solved  by  practical  work  in  the  laboratory,  which,  even 
if  they  are  not  used  for  examination  purposes,  will  nevertheless  afford 
hints  that  may  be  utilized  in  other  ways.  The  recent  examination 
papers  of  the  University  of  the  State  of  New  York  will  assist  in  show- 
ing what  are  deemed  the  most  important  things  in  the  science.  Ellis' 
Papers  in  Inorganic  Chemistry  (London,  Rivingtons ;  New  York,  Long- 
mans), containing  eight  hundred  questions  and  problems,  with  numer- 
ical answers  to  the  latter,  and  a  volume  of  Questions  on  Chemistry,  by 
Jones  (Macmillan),  maybe  found  useful.  Sets  of  questions  in  chemistry 
are  published  every  month  in  the  SCHOOL  WORLD  (London). 


134         INSTRUCTION  IN  THE  CLASSROOM 

different  in  one's  own  hands  from  what  it  appears  with  an 
expert  at  the  helm  that  more  than  enough  remains  to  be  learned 
to  repay  the  repetition.  There  will  be  so  many  physical  con- 
siderations of  a  strange  kind  connected  with  the  apparatus  and 
the  chemical  substances,  that  these  alone,  quite  apart  from  the 
chemical  facts,  make  the  first  laboratory  exercises  sufficiently 
hard  in  spite  of  the  utmost  assistance  the  teacher  can  give. 

Experiments  requiring  special  skill  will  usually  be  shown  by 
the  teacher.  }  To  put  these  in  the  hands  of  beginners  would  be 
to  invite  failure  and  discouragement.  Of  this  nature  are  the 
experiments  of  Hofmann1  on  the  law  of  volumes. 

Experience  is  nowhere  more  needed  than  in  this  work.2  Yet, 
whatever  his  experience,  the  teacher  should  never  show  an  ex- 
Hever  show  Pei"iment  ne  nas  n°t  tried  with  precisely  the  same 
Untried  Ex-  apparatus  and  materials  he  intends  to  employ. 
Different  lots  of  the  same  substance  are  not  al- 
ways identical,  and  even  a  lot  previously  used  will  deteriorate 
and  cease  to  be  trustworthy.  Care  in  these  matters  is  usually 
learned  only  after  several  humiliating  experiences.  The  teacher 
will  also  find  it  difficult  at  first  to  see  the  experiment  as  his 
pupils  view  it,  to  put  himself  back  in  their  place  and  omit  noth- 
ing essential  in  making  clear  the  construction  of  the  apparatus 
and  its  working,  to  draw  attention  to  every  feature  in  the  pro- 
gress of  the  whole  operation,  and  finally  to  wring  from  it  the 
lessons  it  teaches  to  the  last  drop.  In  all  this,  the  interest  of  the 


1  See  Smith,  Laboratory  Outline  of  General  Chemistry,  pp.  iii-iv.     It 
is  a  great  pity  that  the  English  edition  of  Hofmann's  delightful  Introduc- 
tion to  Modern  Chemistry  (London,  1865)  *s  out  °f  print  and  difficult  to 
procure.     It  contains  the  best  models  of  experimental  lectures,  both  as 
regards  presentation  and  illustration,  extant.     The  German  translation 
(Einleitung  in  die  moderne  Chemie,  Braunschweig,  Vieweg,   1877)  has 
reached  its  6th  edition. 

2  See   Newth's  Chemical  Lecttire  Experiments  (Longmans,  Green  & 
Co.,  London  and  New  York,  1899).     Also  Benedict's  Chemical  Lecture 
Experiments  (Macmillan,  London  and  New  York,  1901).     These  works 
will  be  found  indispensable,  even  to  the  practised  experimenter. 

With  few  exceptions,  the  apparatus  used  in  demonstrations  should  be 
the  same  as  that  used  by  the  pupils  in  similar  laboratory  experiments. 


INSTRUCTION  IN  THE   CLASSROOM         135 

class,  which  never  flags  when  anything  is  going  on,  may  be 
utilized  and  directed  so  that,  in  response  to  questions  put  by 
the  instructor  and  by  themselves,  most  of  the  points  just  men- 
tioned are  covered. 

The  preparation  of  experiments  consumes  much  time  and 
requires  some  ingenuity.  Keeping  the  demonstrations  up  to  the 
highest  standard  that  the  equipment  of  the  school  Demandolltjie 
permits  demands  heroic  effort,  and  often  some  Time  of  the 
self-sacrifice  on  the  part  of  a  busy  teacher.  School  Teacher- 
authorities  have  for  the  most  part  still  to  learn  that  a  teacher  of 
science  "cannot  carry  as  many  hours  of  classroom  appointments 
with  efficiency  as  teachers  of  most  other  subjects.  As  Dr. 
Newell  says,1  he  "  needs  time  to  arrange  the  workshop  of  his 
class ;  time  to  consult  with  individual  pupils ;  time  to  repair, 
clean,  arrange,  and  replace  apparatus ;  time  to  clean  up  what 
pupils  and  janitors  will  not  do ;  time  to  mix  solutions,  put  them 
in  properly  labelled  bottles,  and  the  bottles  in  the  customary 
place  ;  time  to  correct  laboratory  notes  and  see  that  the  pupils 
understand  the  corrections ;  time  to  arrange  lecture  experi- 
ments and  remove  the  unsightly  results  before  the  room  is 
again  used ;  time  to  visit  with  classes  the  neighbouring  shops 
and  manufactories  which  illustrate  the  industrial  phases  of  chem- 
istry ;  time  to  read  current  scientific  literature ;  time  to  rest 
physically  and  mentally,  so  that  he  may  come  daily  to  his 
classes  with  that  mental  poise  which  is  essential  to  successful 
teaching."  Reasonable  time  within  school  hours  for  most  of 
these  tasks  is  as  necessary  for  good  teaching  of  chemistry  as 
the  materials  and  laboratory  themselves. 

c.    Stoichiometric  Problems :  —  The  working  of  problems  in 
considerable  numbers  by  individual  pupils  seems  to  be  an  ex- 
ercise too  often  neglected.     This  is  acknowledged 
to  be  a  valuable  aid  in  enforcing  the  quantitative 
character  of  every  chemical  change,  and  in  holding  the  pupil's 
attention  on,  and  making  him  familiar  with  combining  weights 
and  their  use.     More  difficult   problems,  concerned  with  the 

1  SCHOOL  REVIEW,  IX.  (1891),  288. 


136         INSTRUCTION  IN  THE   CLASSROOM 

calculation  of  molecular  and  atomic  weights,  and  other  allied 
subjects  using  the  laws  of  gases,  form  the  readiest  means  of 
clinching  what  may  otherwise  remain  a  mass  of  loose  and 
ephemeral  ideas.  Sample  cases  should  be  worked  in  the 
classroom.  After  the  pupil's  exercises  have  been  corrected, 
it  will  be  found  adv'sable  to  discuss  them  with  the  class.1 

d.  Use  of  the  Text- Book : —  Some  teachers  prefer  to  use  no 
regular  book,  and  instead  refer  their  pupils  to  certain  passages 
in  works  contained  in  the  school  library.  Their  pupils,  how- 
ever, generally  lack  fulness  in  knowledge  of  the  subject.  To 
throw  the  pupil  on  his  own  resources  is  an  excellent  idea,  but 
this  plan  seems  to  carry  it  too  far.  Reading  in  other  books, 
however,  is  also  highly  advisable,  if  there  is  opportunity  for  it. 
In  any  case,  turning  of  the  work  into  humdrum  preparation  of 
so  many  pages  of  printed  matter  daily  is  easily  avoided. 

It  is  well  to  have  some  familiar  source  to  which  the  pupil 
may  turn  for  assistance  in  recalling  old  matters.  There  is  some 
advantage  also  in  the  pupil's  becoming  perfectly  acquainted 
with  the  arrangement  of  one  book,  which  shall  employ  approxi- 
mately the  order  followed  in  the  laboratory.  This  helps  him  in 
getting  a  more  definite  grasp  of  the  relations  of  the  parts  of  the 
science. 

The  chief  reason  for  the  use  of  books,  and  preferably  in  the 
main,  one  book,  lies  in  the  fact  that  there  will  hardly  be  a  single 
A  Text-Book  chemical  change  of  which  the  pupil  can  make  a 
necessary.  complete  study,  if  he  is  thrown  absolutely  on  his 
own  resources.  His  own  work  furnishes  him  with  a  part  only 


1  A  graduated  series  of  problems,  with  answers,  is  given  in  Whiteley's 
Chemical  Calculations  (London  and  New  York,  Longmans,  Green  &  Co.). 
Waddell's  Arithmetic  of  Chemistry  and  Lupton's  Elementary  Chemical 
Arithmetic  (London  and  New  York,  Macmillan)  are  similar  books. 
Many  problems  will  be  found  also  in  Newell's  and  in  Perkin  and  Lean's 
books  already  mentioned,  in  E.  F.  Smith  and  Kellar's  Experiments  in 
General  Chemistry  (Philadelphia,  Elakiston)  and  in  Tilden's  Introduction 
to  the  Sttidy  of  Chemical  Philosophy  (London  and  New  York,  Longmans, 
Green  &  Co.).  The  teacher  will  find  an  admirable  series  of  problems 
in  physical  chemistry  in  Brauer's  Aufgaben  aus  der  Chemie  und  der  physi- 
kalischen  Chemie  (Leipzig,  Teubner,  1900). 


INSTRUCTION  IN   THE   CLASSROOM         137 

of  the  information  necessary  for  reaching  the  chemical  con- 
clusion to  which  his  experiment  points.  If,  for  example,  he 
burns  phosphorus  in  oxygen,  he  sees  a  white  cloud.  He  may 
succeed  in  showing  that  this  is  a  solid,  that  the  gas  is  used  up, 
and  that  the  solid  is  the  only  product.  These  things  are  within 
his  powers  of  observation,  although  the  experiment  seldom  seems 
to  be  carried  even  as  far  as  this.  But  even  so,  he  can  only  in- 
fer that  a  solid  compound  of  the  two  elements  has  been  formed. 
His  study  of  the  problem  has  been  suspended  before  it  could 
be  clinched,  on  account  of  the  difficulty  in  measuring  the  com- 
position of  the  product.  Even  if  he  could  do  this,  however, 
he  would  still  require  to  get  the  combining  weights  from  the 
book.  Usually  he  gets  both,  in  the  formula,  from  this  or  the 
teacher.  I  have  seen  many  note-books  in  which  the  observa- 
tion of  white  smoke  and  the  inference  that  the  "  product  was 
P2O5"  were  the  sole  entries.  It  is  worse  than  waste  of  time  to 
encourage  the  pupil  to  make  sham  inductions  like  this  from 
ridiculously  inadequate  data.  When  he  has  been  told  explicitly 
that  his  laboratory  work  is  not  expected  to  furnish  all  the  neces- 
sary information,  he  appreciates  the  possibility  of  extending  this 
information  by  more  elaborate  experiments.  If,  on  the  con- 
trary, he  is  left  in  doubt  on  this  point,  and  yet  is  asked  to  write 
the  equation  for  every  chemical  change  (*'.  e.  to  draw  a  quan- 
titative conclusion  from  qualitative  data)  he  will  perceive  the 
existence  of  an  imposture,  even  if  he  cannot  point  out  where  it 
lies. 

This  is  not  criticism  of  an  unreal  state  of  affairs.  Much 
chemistry  teaching  is  like  setting  out  to  invite  a  man  to  test  a 
stair,  and  then  almost  carrying  him  up  bodily.  He  not  only 
learns  nothing  about  the  soundness  of  its  construction,  but  he  is 
led  to  suspect  that  it  was  unsound  because  he  was  continually 
juggled  out  of  the  chance  to  test  it.  Our  laboratory  manuals 
too  .often  give  no  definite  indication  of  how  far  induction  may 
go,  and  they  seldom  draw  the  line  sharply  between  the  knowl- 
edge obtainable  from  this,  and  that  which  must  be  obtained 
from  some  other  source,  if  it  is  to  be  obtained  at  all.  It  seems 


138          INSTRUCTION  IN   THE   CLASSROOM 

to  me  that,  unless  the  laboratory  work  is  all  reduced  to  pluck- 
ing unopened  buds,  for  mere  practice  in  plucking,  the  practical 
work  and  the  book  must  go  hand  in  hand.  The  laboratory 
work  is  indispensable.  It  gives  real  knowledge  of  a  kind  no 
book  can  furnish.  But  the  book  must  be  employed  also  unless 
the  instruction  is  to  progress  with  the  leisure  and  resources  of 
original  discovery  (cf.  Heuristic  Method,  p.  105). 

e.  The  Importance  of  keepi?ig  the  Stibject  in  Contact  with 
Eve.ry-day  Life :  *  —  There  are  two  dangers  into  which  the 
teacher  of  chemistry  may  fall.  One  is  that  of  so  circumscrib- 
ing the  view  which  he  gives  of  the  science  that  it  is  shut  in  by 
a  high  fence  which  precludes  even  a  glimpse  of  the  world  be- 
yond and  its  chemistry;  the  other  is  that  of  digression  into 
various  attractive  and  more  or  less  famjliar  subjects,  which 
may  thus  be  allowed  to  interfere  with  the  systematic  teaching 
of  the  science.  While  avoiding  the  real  danger  of  excessive 
digression >  we  must  at  all  hazards  save  the  subject  from  the 
former  abuse  by  the  judicious  employment  of  legitimate  means 
of  illustration  and  vitalization. 

This  procedure  is  helpful  to  the  instruction  in  the  science 
itself.  A  strange  subject,  dealing  entirely  with  foreign  material, 
Unfamiliar  can  never  be  interesting  to  the  majority  of  pupils. 
Materials.  Their  natural  craving  for  a  tinge  of  human  interest  I 
in  everything  is  starved.  Surely  the  study  of  a  subject  which  / 
is  as  intensely  interesting  historically  and  industrially  as  chem- 
istry is,  need  never  suffer  from  this  limitation.  On  the  other 
hand,  we  cannot  possibly  confine  ourselves  to  common  ma- 
terials in  attempting  to  teach  the  science.  In  speaking  of 
oxygen,  we  immediately  encounter  barium  peroxide,  mercuric 
oxide,  and  potassium  chlorate.  If  we  were  to  attempt  to  avoid 
strange  bodies  like  these,  we  should  be  bound  to  leave  our- 
selves without  means  of  systematically  building  up  and  rounding 
out  the  architecture  of  the  science.  We  simply  cannot  summon 
it  forth  from  a  mass  of  information  about  cooking,  agriculture, 
rusting,  and  photography  by  any  legerdemain.  The  chemistry 

1  See  pp.  68,  74,  129,  138,  and  177. 


INSTRUCTION  IN  THE   CLASSROOM          139 

of  many  of  these  things,  and  the  experimental  work  involved  in 
studying  it,  are  too  difficult  for  beginners.  But  when  we  speak 
of  the  three  bodies  just  mentioned,  for  example,  we  can  refer 
to  Erin's  oxygen  process,  to  Priestley  and  his  work,  and  to 
matches,  so  as  to  facilitate  the  introduction,  on  a  friendly  foot- 
ing, of  these  barbarous  materials,  and  so  break  down  the  shy- 
ness and  reserve,  if  not  distrust,  with  which  new  acquaintances 
will  naturally  be  formed  by  the  beginner. 

An  illustration  will  help  still  further  in  showing  what  is  meant. 
Suppose  we  state  that  aluminium  is  made  by  decomposition  of 
the  oxide  by  means  of  electricity,  and  that  the  equa- 
tion is  2A12O3  ->4A1+3O2.  Bald  teachifig-Tjf^this^ 
kind  is  not  uncommon.  Sometimes,  in  a  misdirected  attempt  to 
animate  the  subject,  tee  operation  is  explained  in  terms  of  the 
atomic  theory.  This,  however,  inevitably  renders  it  more  in- 
animate than  before,  and  transfers  it  at  once  to  a  ghostly  and 
unreal  world.  How  much  better  to  show  the  materials ;  to 
describe  the  plant,  its  location,  and  the  water  power  it  uses ;  to 
explain  the  process  with  its  exciting  details  from  the  bath  of 
molten  cryolite  to  the  blazing  block  of  carbon  at  which  the 
oxgen  is  liberated.  The  action  of  the  electricity  will  be  better 
appreciated  if  electrolysis  of  a  dilute  acid,  or  better  still  of  cupric 
sulphate,  is  shown.  All  this  need  not  be  given,  and  certainly 
nothing  like  as  much  as  this  in  connection  with  every  chemical 
action.  But  once  or  twice  in  every  lesson  something  is  needed 
to  revive  the  drooping  imagination  of  the  pupil,  and  give  him  a 
vivid  stereoscopic  view  of  chemistry  as  it  is.  Again,  when  we 
deal  with  the  preparation  of  nitric  acid,  the  method  will  be  for- 
gotten infallibly  if  some  precautions  are  not  taken.  Reiteration 
is  not  a  remedy  !  Why  not  contrast  it  with  sulphuric  acid,  which 
cannot  be  made  from  the  sulphates,  found  in  great  quantities  in 
nature,  for  easily  explained  reasons.  On  the  other  hand  nitric 
acid,  although  natural  nitrates  are  expensive,  cannot  be  made 
economically  from  the  elements.  In  connection  with  its  syn- 
thesis we  have  Cavendish's  work  on  the  investigation  of  the 
residual  gas  in  air,  then,  and  for  long  afterwards,  supposed  to  be 


140         INSTRUCTION  IN  THE   CLASSROOM 

all  nitrogen,  and  Lord  Rayleigh's  recent  success  in  obtaining 
argon  by  use  of  Cavendish's  principle  (this,  by  the  way,  is 
an  admirable  illustration  of  the  effect  of  removing  one  factor 
in  a  reversible  action).  Finally,  the  sources  of  the  natural 
nitrates  and  their  production  under  the  influence  of  bacteria  are 
available  for  lending  colour  and  interest  to  the  subject.  It  must 
be  repeated  that  giving  all  of  this  would  take  time  which  cannot 
be  spared,  but  something  may  be  picked  out  in  connection  with 
almost  every  action  in  chemistry  which  will  be  helpful  in  mak- 
ing it  comprehensible  or  memorable. 

The  employment  of  illustrations  from  things  outside  the  labo- 
ratory also  increases  the  usefulness  of  the  instruction.  The  teacher 
in  the  secondary  school,  in  view  of  the  fact  that  his  pupils  are  most 
of  them  receiving  from  him  their  sole  preparation  for  life,  has  a 
certain  responsibility  in  this  direction  which  he  cannot  avoid. 
In  a  later  section  (p.  177)  we  shall  have  occasion  to  suggest  a 
number  of  questions,  for  reply  to  most  of  which  the  basis  at 
least  is  to  be  found  in  elementary  chemistry.  There  is  no  use 
claiming  that  chemistry  is  a  study  of  real  things  and  not  an  arti- 
ficial discipline,  unless  we  show  that  it  is  so.  It  is  not  suggested 
that  the  applied  chemistry  should  be  taught,  but  only  that  its 
existence  should  be  made  plain  in  the  most  pointed  manner. 
We  need  not  and  must  not  make  too  much  of  this  aspect. 
Without  there  being  any  necessity  for  turning  aside  to  teach 
domestic  science,  for  example,  and  leaving  chemistry  altogether, 
there  are  illustrations  of  all  sorts  from  various  more  or  less  every- 
day matters  which  must  suggest  themselves  continually  to  the 
thoughtful  teacher. 

Take,  for  example,  oxidation.  Aside  from  the  hackneyed 
illustrations  connected  with  rusting,  life,  and  decay,  the  subject 
Still  Other  suggests  the  way  in  which  blue  clay  becomes  brown 
Illustrations.  when  exposed  to  the  air  through  the  change  of  the 
iron  it  contains  from  the  ferrous  to  the  ferric  condition  ;  the  way 
in  which  paint  '  dries '  through  absorption  of  oxygen  by  the 
solidifying  oil ;  the  way  anglesite  (PbSO4)  and  cerussite  (PbCO3) 
are  formed  from  galena  (PbS)  and  are  commonly  found  en- 


INSTRUCTION  IN  THE   CLASSROOM          141 

crusting  the  veins  of  the  latter ;  and  the  fact  that  deposits  of 
ores  of  copper  are  mainly  carbonate  and  oxide  at  the  surface, 
and  pass  into  sulphide  as  the  exploration  of  greater  depths  pro- 
ceeds. Reduction  is  illustrated  by  the  various  photographic  de- 
velopers and  by  the  genesis  of  native  copper  from  cuprite ; 
adsorption  by  dyeing  of  cloth,  the  action  of  mordants,  the  for- 
mation of  '  lakes/  and  the  effect  of  heating  a  glass  bulb  after  it 
has  just  been  evacuated  to  the  point  at  which  it  begins  to  show 
the  X-rays.1  Reversible  actions  are  illustrated  by  the  storage 
battery  ;  osmotic  pressure  by  the  root  pressure  in  plants;2  pre- 
cipitation of  calcium  carbonate  by  the  formation  of  coral  and 
shells  through  the  action  of  ammonium  carbonate  excreted  by  the 
organism  inter-acting  with  the  calcium  sulphate  in  the  sea-water ; 
the  subject  of  the  lowering  of  vapour  pressure  in  solutions  by  the 
spontaneous  way  in  which  impure  table  salt  becomes  moist,  and 
ice  is  melted  by  contact  with  salt ;  dissociation  of  the  true  or 
reversible  kind  by  lime  burning ;  the  displacement  of  metals  by 
toning  in  photography  ;  solution  in  the  broader  sense  by  refer- 
ence to  alloys  and  to  gems  like  the  sapphire  or  yellow  diamond. 
The  judicious  use  of  this  sort  of  illustrations  involves  not  a 
loss  but  a  saving  of  time,  and  it  fixes  points  of  real  chemical 
value  in  the  memory.  The  mention  of  things  which  other  Benefits 
are  natively  interesting  in  connection  with  other  of  illustration, 
things  which  are  not  so  is  one  of  the  best  means  of  lending  in- 
terest to  facts  that  might  otherwise  seem  dry.  The  practice  is 
useful  so  long  as  it  is  employed  with  this  end  in  view.  It  ceases 
to  be  so  when  the  chemistry  becomes  secondary,  and  that  which 
should  be  simply  an  illustration  is  dwelt  upon  to  such  an  extent, 
or  in  such  a  way,  that  it  displaces  the  chemical  fact  from  the 
field  of  view  entirely.  Another  advantage  of  this  procedure  is 
that  it  relates  the  subject  continually  to  the  physics,  geology,  and 
biology  which  the  pupil  may  have  already  studied  or  may  be 

1  Air  adhering  to  the  glass  is  liberated,  and  the  X-rays  vanish,  to  re- 
appear only  when  the  pump  has  been  started  again. 

2  Applications  of  the  theory  of  solutions  to  physiology  will  be  found 
in  Jones'   Theory  of  Electrolytic  Dissociation  (Macmillan),  Chapters  II. 
and  IV. 


I42          INSTRUCTION  IN  THE   CLASSROOM 

about  to  study.  It  is  at  least  as  important  that  the  teacher  in 
the  secondary  school  should  give  a  general  view  of  science,  and 
of  the  relations  of  the  sciences,  as  that  he  should  give  a  sharply 
focused  view  of  one. 

Many  chemists  are  conscientiously  and  systematically  opposed 
to  encouraging  the  introduction  of  anything  which  is  in  the  least 
Danger  in  degree  likely  to  divert  the  attention  of  the  pupils 
the  Abuse  of  from  the  science.  They  state,  and  probably  with 

justice,  that  there  is  far  too  much  so-called  chemi- 
cal instruction  in  the  schools  which  is  perverted  into  the  teach- 
ing of  odds  and  ends  about  various  domestic  and  industrial 
applications  of  chemistry.  I  fear  greatly,  therefore,  that  what 
has  just  been  said  may  be  open  to  misconstruction,  and  may 
be  taken  as  advocating,  or  in  some  way  countenancing  such  a 
misuse  of  illustrative  material.  To  be  perfectly  clear,  let  me 
say  that  the  object  of  the  references  to  every-day  life  will  be 
defeated  if  they  give  occasion  for  long  descriptions  of  these 
matters.  It  is  a  continual  but  brief  reference  to  these  matters 
in  their  chemical  aspect,  which  shall  show  that  the  chemistry  of 
the  laboratory  and  the  classroom  is  the  same  as  that  of  the 
universe,  and  that  there  is  such  a  thing  as  chemistry  in  the  uni- 
verse, that  is  suggested,  and  not  such  prolonged  tours  of  super- 
ficial inspection  of  the  chemical  universe  as  will  prevent  that  of 
the  laboratory  and  classroom  from  taking  definite  form.  The 
use  of  judgment  of  the  sanest  description  is  imperatively 
needed. 

The  facts  cited  for  the  purpose  of  illustration  must  be  sub- 
jected to  careful  scrutiny  before  currency  is  given  to  them.  The 

reader  may  recall  the  statement  in  a  familiar  work 
Scientific  that  "throwing  water  upon  conflagrations  results 

in  the  dissociation  of  the  compound  into  the  gases 
hydrogen  and  oxygen,  which,  in  reuniting,  add  fury  to  the  flames 
and  increase  the  devastation."  There  are  many  popular  notions 
about  the  scientific  aspect  of  common  things  which  contain  fal- 
lacies more  difficult  to  trace  than  is  the  absurdity  in  this.  Then, 
too,  the  chemistry  of  many  common  things  is  but  little  known. 


INSTRUCTION  IN  THE   CLASSROOM          143 

The  contradictory  statements  about  the  reason  of  the  harmful 
effects  of  the  atmosphere  of  overcrowded  rooms,  for  example, 
suggests  that  more  knowledge  of  the  subject  is  necessary  before 
it  can  be  admitted  to  the  elementary  classroom.  Again,  the 
chemistry  of  many  familiar  things  is  hard.  Domestic  science 
and  agriculture  are  difficult  to  relate  intelligibly  to  elementary 
chemistry.  Soap-making  can  be  explained,  but  the  view  of  the 
facts  connected  with  cooking  and  digestion  afforded  by  the 
standpoint  of  the  pupil  in  the  elementary  school  must  be  too 
superficial  and  distant  to  make  it  suitable  for  incorporation  in 
the  elementary  course.  The  treatment  of  these  subjects  must 
for  the  most  part  degenerate  into  the  giving  of  mere  miscella- 
neous information. 

At  the  risk  of  repetition  let  it  be  said  again  that  teaching  the 
chemistry  of  every-day  life  is  not  the  end  of  the  course  in  the 
secondary  school.  Its  object  is  the  giving  of  discipline  through 
a  knowledge  of  chemistry  in  a  broad  but  strictly  scientific  sense. 
Reference  to  the  chemistry  of  matters  of  common  knowledge 
is  suggested  simply  as  one  means  of  attaining  the  main  end  of 
the  course,  by  making  the  subject  memorable,  attractive,  and 
digestible. 

f"  f.     Necessity  for  Unification  of  the    Whole  :  —  Although  the 
necessity  for  unification  has  been  more  than  hinted  at  already, 
too  much  emphasis  cannot  be  laid  upon  this  point. 
In  a  multitude  of  details  there  is  no  wisdom.     The   Science 


mastery  of  the  science  consists  not  so  much  in  steady 
accumulation  of  knowledge  as  in  building  up  habits  of  Habits. 
of  observation  and  thought,  and  cultivating  a  chemical  intelli- 
gence. No  point  in  technique,  observation,  or  generalization  is 
ever  past  or  disposed  of.  The  pupil  is  slow  to  appreciate  the 
universality  of  the  ultimate  constituents  of  chemical  thought  and 
work,  and  requires  to  have  them  brought  to  his  attention  again 
and  again.  The  teaching  of  a  science  is  a  weaving  process. 
The  same  warp  runs  through  all,  and,  while  the  pattern  develops 
and  no  strand  is  precisely  like  the  preceding  one,  the  result 
should  be  an  harmonious  development  of  the  design  as  a  whole. 


144         INSTRUCTION  IN  THE   CLASSROOM 

Each  new  fact  is  centrifugal  in  tendency  and  at  first  introduces 
a  foreign  element.  The  important  thing  is  not  the  adding  of 
new  facts,  but  their  utilization  in  the  creation  of  that  more 
recondite  entity,  the  pupil's  general  grasp  of  the  science.  The 
quality  of  the  result  depends  not  on  the  amount  or  variety  of 
the  material,  but  on  the  perfection  with  which  it  has  been 
assimilated^ 

g.  Some  Misleading  Words :  —  One  of  the  most  fruitful 
sources  of  misconception  lies  in  the  ordinary  phraseology  of 
•Strong'  chemistry.  Thus  the  word  strong  is  very  much 
Acids.  overworked.  It  is  used  for  active  in  reference 

to  the  chemical  tendencies  of  oxygen,  chlorine,  certain  acids, 
and  so  forth.  It  is  used  in  connection  with  solutions  when 
great  concentration  is  meant.  It  is  even  used  for  stable.  It 
will  be  found  most  satisfactory  to  use  the  proper  one  of  these 
three  terms  in  the  classroom  and  to  exclude  the  word  strong 
altogether. 

The  words  stable  and,  the  converse,  unstable  are  used  in  two 
ways.  Thus  sodium  chloride  and  nitrogen  iodide  are  respec- 
4 Stable'  tively  styled  stable  and  unstable,  in  consequence  of 
Bodies.  their  behaviour  when  heated,  and  properly  so. 

Phosphorus  trichloride  is  exceedingly  stable  by  this  test,  but  is 
often  spoken  of  as  unstable  because  moist  air  decomposes  it. 
In  this  sense  everything  might  be  considered  unstable,  since 
everything  undergoes  change  when  treated  with  a  suitable  chem- 
ical agent. 

The  pupil  eagerly  learns  a  word  and  forgets  the  fact  it  was 
used  to  describe,  and  our  words  are  often  so  badly  chosen  that 

_         .       afterwards,  when  the  learner  tries  to  reproduce  the 
4  Water  of 
Crystalliza-     idea  from  the  word,  he  makes  the  most  egregious 

blunders.  He  will  say  that  water  of  crystallization, 
for  example,  is  water  needed  to  make  the  particular  substance, 
or  all  substances,  take  the  crystalline  form.  He  will  say  it  is 
not  chemically  combined,  because  the  word  suggests  a  physical 
condition  simply.  It  would  be  better  to  use  the  term  hydrates 
exclusively  (p.  96).  At  the  end  of  the  course,  he  will  still  say 


INSTRUCTION  IN   THE   CLASSROOM          145 

that  oxidation  is  combination   with  oxygen  regardless  of  the 
many  other  phenomena  it  covers.      He  will  say  a  metal1  is 
a   metallic-looking    substance    and  call    arsenic  a   « oxidation.' 
metal,  regardless  of  the  fact  that  the  term  has  a    '  Metal.' 
use  of  its  own  in  chemistry.     He  will  say  that  a  saturated  solu- 
tion contains  all  that  the  liquid  can  hold  of  the  dissolved  body, 
and  a  supersaturated  one  more  than  it  can  hold  (  !) ,    <  satura- 

reirardless  of  the  fact  that  the  terms  have  nothing  to   tion*' 

'  Super- 
do  with  what  the  liquid  can  hold,  but  concern  only  saturation.' 

what  it  can  take  up  from  a  given  sample.  A  solution  of  a  cer- 
tain concentration  may  be  saturated,  unsaturated,  and  supersat- 
ured  all  at  the  same  time  toward  different  forms  of  '  sodium  sul- 
phate.' 2  Our  ideas  in  chemistry  have  so  often  been  labelled 
wrongly  that  we  must  discredit  the  label  while  teaching  the 
idea ;  our  terms  often  obliterate  and  obscure  the  very  distinc- 
tions they  are  intended  to  record.  In  examinations  we  must 
ask  for  illustrations,  to  make  sure  that  the  word  has  not  been 
learned  and  its  definition  memorized  without  comprehension 
of  what  it  really  covers. 

Some  words  are  as  yet  without  definite  signification.     Oxygen 
and  ozone,  rhombic  and  monoclinic  sulphur,  red  and  yellow 
phosphorus  are  called  pairs  of  allotropic  modifi- 
cations.    Yet  the  first  pair,  and  probably  the  last, 
are  chemically  distinct  substances,  while  the  second  is  a  pair  of 
physical  states  of  the  same  body,  like  ice  and  water. 

Absurdities,  like  the  description  of  a  metal  as  "  brittle  and 
ductile,"  are  so  common  that  we  must  heed  the  warning  and 
make  sure  that  even  the  definite  terms  are  not  being  used  as  if 
they  were  a  meaningless  jargon. 

h.  Some  Common  Fallacies :  —  There  are  a  few  blunders,  that 
have  long  since  been  recognised  to  be  such  by  chemists,  which 
still  hang  pertinaciously  round  elementary  instruction.  For 
example,  the  formation  of  hydrogen  chloride  by  the  action  of  sul- 
phuricacid  upon  common  salt  does  not  prove  the  superior  activity 

1  Cf.  Tilden,  Hints  on  the  Teaching  of  Elementary  Chemistry,  63-66. 
Cf.  Walker,  Introduction  to  Physical  Chemistry  (Macmillan),  50. 

10 


146          INSTRUCTION  IN  THE   CLASSROOM 

('  strength  ')  of  sulphuric  acid.  Under  other  conditions  hydro- 
chloric acid  displaces  sulphuric  acid  from  sodium  bisulphate 
almost  as  completely.1 

The  so-called  law  of  Berthollet  in  regard  to  the  formation 
of  precipitates,  even  in  its  least  objectionable  form  of  statement, 
is  a  half  truth  or  less.  So  distinguished  a  chemist 
Precipitation ' as  ^ie  ^ate  Pr°fessor  Cooke  makes  something  like 
nonsense  of  it  when  he  says,2  "  When  materials 
are  brought  together  in  solution  there  is  always  a  tendency  to 
make  such  a  transfer  of  their  constituent  parts  as  will  produce 
insoluble  compounds."  It  must  be  remembered  that  the  prin- 
ciples of  chemical  equilibrium 3  alone,  and  not  a  tendency  to 
produce  insoluble  substances,  or,  above  all,  any  superior 
'  affinity  '  can  explain  this  behaviour. 

The  current  explanations  of  the  heat  produced  when  sub- 
stances like  sulphuric  acid  and  caustic  potash  are  dissolved  in 
water  are  almost  all  of  doubtful  correctness.  The 
Solution.'  present  condition  of  the  science  does  not  permit  us 
confidently  to  offer  any  explanation  and  in  elemen- 
tary instruction  it  is  safest  to  say  so. 

The  early  misconceptions  produced  by  injudicious  teach- 
ing in  matters  like  those  just  cited  are  wonderfully  lasting 
and  can  only  be  eradicated  afterwards  with  great  difficulty,  if 
at  all. 

i.  T/te  Grammar  of  Science : — The  ordinary  treatises  on  the 
sciences  omit  all  explanation  of  the  fundamental  conceptions 
of  the  scientific  method.  Indeed  it  would  be  fortunate  if  they 
also  avoided  introducing  confusions  of  thought  and  blunders  of 
the  grossest  kind  when  they  touch  the  subject  indirectly.  The 
teacher  of  science  must  make  up  for  this  lack,  and  perhaps 
correct  these  misconceptions,  by  the  study  of  some  work  dealing 
with  the  subject.  We  have  space  to  mention  two  or  three 
examples  only. 

1  A.  Smith,  Laboratory  Outline,  p.  26. 

2  Laboratory  Practice,  p.  41. 

8  See  Carnegie,  Law  and  Theory  in  Chemistry  (Longmans,  Green  & 
Co.)  chapter  VII.,  particularly  p.  205. 


INSTRUCTION  IN  THE   CLASSROOM         147 

Explanation,1  its  nature  and  correct  use  seem  to  be  frequently 
misconceived.  An  explanation  never  attempts  to  state  the 
reasons  for,  or  causes  of  scientific  facts.  We  can  ,Ex  lana 
give  no  reason  for  chemical  behaviour,  nor  do  we  tion » in 
regard  it  as  proceeding  from  ultimate  causes  (in 
the  sense  of  active  originators  which  do  things).  ,An  explana- 
tion is  simply  a  description  which  relates  a  thing  or  idea  to 
other  more  familiar  things  or  ideas.  In  this  way  we  explain 
the  hastening  of  the  evolution  of  hydrogen,  when  a  little  cupric 
sulphate  is  added,  by  reference  to  what  we  know  about  electric 
couples.  An  illustration  fully  worked  out  in  detail  has  already 
been  given  in  connection  with  the  discussion  of  the  use  of  the 
imagination  (p.  131).  The  employment  of  terminology  is  not 
explanation.  For  example,  to  call  an  action  'catalytic,'  clas- 
sifies, but  does  not  explain  it.  Note  also  that  to  call  the 
tendency  to  chemical  action  '  affinity 7  simply  substi- 
tutes the  one  word  for  the  four.  It  also  classifies, 
in  so  far  as  it  distinguishes  this  tendency  by  name  from  cohesion 
and  other  forces.  It  most  emphatically  does  not  explain,  for, 
instead  of  relating  a  fact  to  a  closely  allied  but  more  familiar 
fact,  it  deliberately  relates  the  simple  fact  to  a  complex  set  of 
entirely  foreign  ideas  connected  with  the  word  affinity  (namely, 
those  of  kinship,  sympathy,  and  attraction),  which  are  pure 
importations,  and  so  the  word  confuses  instead  of  explaining. 
Thinking  that  these  ideas  are  germane  to  the  thing  itself,  is,  to 
apply  a  sentence  of  Wundt's,  "  one  of  those  numerous  self- 
deceptions  which  are  no  sooner  stamped  in  verbal  form  than 
they  forthwith  thrust  non-existent  fictions  into  the  place  of 
reality."  As  a  name  for  a  thing  and  a  means  of  classification, 
affinity  is  a  good  term ;  as  an  explanation,  it  is  a  failure,  for, 
in  the  language  of  the  schoolmen,  at  the  best  it  is  simply 
a  case  of  explaining  idem  per  idem,  and  at  the  worst  of  ob- 


1  See  W.  K.  Clifford.  Aims  and  Instruments  of  Scientific  Thought  in 
his  Lectures  and  Essays,  particularly  pp.  101-103  (2nd  ed.  1886).  Also 
Stallo,  Concepts  and  Theories  of  Modern  Physics,  chapter  VIII.,  particu- 
larly pp.  104-110. 


148         INSTRUCTION  IN  THE   CLASSROOM 

scurum  per  obscurius,  for  it  only  adds  greatly  to  the  total  to  be 
explained. 

The  meaning  of  law  in  natural  science  seems  far  from  being 
generally  known.     My  own  recollection  as  a  student  shows  that 

« Law  'in  for  a  lonS  time  *  was  in  utter  confusion  as  to  the 
Natural  origin  and  meaning  of  the  laws  of  physics  and  chem- 
istry, because  the  meaning  of  the  word  Maw7  had 
never  become  clear  to  me.  Its  usage  was  frequently  so  confus- 
ing that  its  significance  could  not  be  inferred.  This  experience 
I  am  convinced  is  not  exceptional.  The  use  of  the  word 
even  in  scientific  books  is  so  often  incorrect  that  it  would  be 
astonishing  if  teachers  were  not  in  danger  of  misleading  their 
pupils.  The  word  is  commonly  accepted  as  applying  to  some 
dogma  which  requires  no  defence  and  must  be  accepted  with- 
out question,  or  some  belief,  like  that  in  our  own  existence  as 
conscious  beings,  which  is  more  easy  to  accept  as  an  intuition 
than  to  support  by  argument.  Another  misuse  of  the  term  adds 
additional  confusion.  We  find  it  stated  that  some  gases  do 
not  obey  Boyle's  law  ;  again,  we  learn  that  Boyle  discovered  this 
law,  about  a  century  and  a  half  after  Columbus  discovered 
America.  One  writer  speaks  thus :  "  Nature  .  .  .  follows  laws 
which  are  always  operative  under  the  same  conditions.  Vary 
the  conditions  of  an  experiment,  and  new  laws  are  liable  to  in- 
tervene and  change  the  result.  The  essence  of  law  is  uniformity 
of  action  under  like  conditions."  The  italics  are  in  the  original. 
Of  the  various  senses  tn  which  the  word  is  used,  two  only 
seem  to  be  legitimate  in  science.  In  the  narrower  of  these 
two  senses,1  a  law  is  simply  an  exceedingly  brief  statement 
which  embraces  an  immense  range  of  separate  facts.  In  a 
broader  sense  the  term  may  be  used  of  the  uniform  behaviour 
itself  which  is  described  in  the  statement  of  the  law.  It  is 
therefore  either  the  statement  of  a  fact  or  it  is  a  fact.  In  the 
latter  sense  it  is  pre-eminently  a  fact  of  the  highest  order. 
Thus  the  so-called  law  of  falling  bodies,  for  example,  is  either 

1  Karl  Pearson,  Grammar  of  Science,  chapter  III.     See  also  The  Duke 
of  Argyle,  The  Reign  of  Law. 


INSTRUCTION  IN   THE   CLASSROOM         149 

that  which  tells  us  in  one  brief  statement  all  about  the  fall  of 
every  sort  of  material,  whether  it  be  a  feather,  a  bullet,  or  the 
moon,  and  whether  it  falls  towards  the  earth  or  some  other 
celestial  body,  or  it  is  the  uniform  behaviour  itself  of  bodies  left 
free  to  move  under  each  other's  influence.  In  the  former  and 
stricter  sense  this  law  was  not  discovered,  however,  for,  unlike 
the  New  World,  it  did  not  exist  previous  to  its  '  discovery ' 
and  does  not  now  exist  objectively  in  nature.  It  was  a  state- 
ment invented  or  made  from  the  comparison  of  multitudes  of 
single  observations.  Laws  in  this  sense  are  thus  true  only  so 
long  as  they  express  successfully  the  facts  with  which  they  deal. 
When  we  discover  by  more  careful  observation  that  gases  do 
not  change  their  volume  exactly  in  the  inverse  proportion  of 
the  pressure,  it  is  not  the  gas  which  'disobeys'  the  law,  but 
the  law  which  fails  to  express  the  facts  exactly.  Laws  are  not 
active  agents  ;  they  do  not  '  operate  '  under  any  conditions, 
nor  do  they  '  act '  either  uniformly  or  otherwise,  and  new  laws 
do  not  '  intervene ; '  the  humble  law-maker  has  to  change  his 
law  when  he  finds  that  the  facts  do  not  support  it  in  its  existing 
form.  In  the  latter  sense  the  law  is  the  fact  itself,  the  fashion 
of  behaving.  This  was  discovered,  but  it  is  not  of  the  order  of 
a  mandate  of  some  recognised  authority,  and  the  word  l  dis- 
obey '  is  inapplicable.  It  is  not  supported  by  a  police  force, 
like  legislative  law,  and  therefore  does  not  ' operate,'  'act,' 
or  '  intervene,'  even  in  the  figurative  sense  in  which  these 
terms  are  used  of  the  law  of  the  land. 

These  unfortunate  conventional  modes  of  expression  make  it 
exceedingly  desirable  that  the  teacher  should  guard  himself, 
first  in  his  own  mind,  and  then  in  the  language  he  uses,  most 
carefully  against  putting  the  idea  of  law  in  a  wrong  light.  No 
single  thing  can  do  more  than  the  misuse  of  this  term  to  per- 
vert completely  the  pupil's  whole  idea  of  scientific  method  and 
perspective,  and  to  undo  on  a  large  scale  what  observation  and 
induction  are  trying  to  do  on  a  small  one. 

Of  the  matters  coming  up  in  elementary  chemistry,  the  princi- 
ples of  definite  and  multiple  proportions  and  combining  weights 


150          INSTRUCTION  IN   THE   CLASSROOM 

are  laws  because  they  state  facts,  and  facts  of  the  widest  bearing. 
On  the  other  hand,  Avogadro's  statement,  while  it  is  frequently 
called  a  law,  is  not  a  fact  of  the  same  order  as  the  others  at 
all,1  It  is  a  part  of  the  molecular  theory  of  matter.  If  it  be  a 
fact,  as  it  probably  is,  it  is  reached  remotely  by  inference,  and 
not  directly  by  experiment. 

Misconception  is  particularly  liable  to  occur  in  connection 
with  the  use  of  the  word  cause.  When  anything  unusual  or 
unfortunate  occurs  in  every-day  life,  we  immediately 
Natural  ask  whose  activity  or  negligence  '  caused '  the  occur- 

Science.  rence.  We  thus  acquire  the  habit  of  looking  for 

some  active  agent  whose  intervention  is  indispensable  for  the 
production  of  certain  results.  We  have  no  justification  for  the 
use  of  the  word  cause  in  this  sense  in  the  scientific  study  of 
nature.  We  note  occurrences,  such  as  those  connected  with 
certain  motions  of  bodies,  and  we  sum  up  the  nature  of  these 
occurrences  in  brief  statements,  of  which  the  most  condensed  is 
known  as  the  law  of  gravitation.  Observation,  however,  leads  us 
to  the  discovery  of  no  active  agent  whose  intervention  brings  the 
phenomena  about.  We  do  not  know  that  the  heavenly  bodies 
will  move  to-morrow  as  they  do  to-day,  or  that  iron  will  rust  in 
the  future  under  the  same  conditions  as  in  the  past.  We  regard 
it  as  probable  in  the  highest  degree  that  these  occurrences  will 
repeat  themselves,  but  the  relation  is  one  of  probability  and  not 
of  necessity.  We  know  the  fact  of  each  occurrence  as  a 
separate  thing,  and  our  general  statement  in  regard  to  the 
occurrences  has  no  power  of  enforcement  for  the  future.  In 
science,  causes,  in  the  sense  of  active  agents  which  originate 
occurrences,  do  not  exist.  It  is  useless,  therefore,  to  permit 
our  minds  to  search  for  causes  of  this  description. 

Yet  we  have  a  tendency  to  furnish  the  link,  which  our  habit 
of  thought  suggests  as  needful,  by  attaching  the  name  of  cause 
to  something,  and  sometimes  in  doing  this  the  term  is  grossly 
misused.  For  example,  we  sometimes  hear  the  law  of  gravi- 

1  See  Ostwald,  Outlines  of  General  Chemistry  (Macmillan),  chapter 
VII.,  in  which  the  terms  hypothesis  and  postulate  are  used. 


INSTRUCTION  IN   THE    CLASSROOM          151 

tation  spoken  of  as  the  cause  of  the  behaviour  of  falling  bodies. 
The  mere  statement  which  in  one  phrase  epitomizes  all  the  be- 
haviour of  falling  bodies,  should  surely  be  the  very  msnae  of 
last  thing   to  which  we  should  ascribe  the  power   the  Word 
of  bringing  about  occurrences  which  it  simply  de- 
scribes.    Even  if  we  apply  the   term  law  to  the  uniform  be- 
haviour  itself,    this    uniform     behaviour    may    explain    future 
occurrences,  but  it  is  not  the  cause  of  them. 

A  study  of  occurrences  scientifically  shows  that  they  may  be 
related  in  two  ways.  In  the  first  place,  certain  phenomena  are 
observed  always  to  appear  simultaneously.  Occurrences  con- 
nected in  this  way  are  described  technically  as  being  related 
by  co-existence.  The  word  cause  cannot  be  employed  in  con- 
nection with  any  of  them. 

The  other  relation  which  may  exist  between  phenomena  is 
that  of  sequence.  We  pass  hydrogen  over  a  heated  oxide  and  it 

is  reduced,  or  we  subject  a  match  to  friction  and  a  , 

Correct  use 

chemical  change  occurs.     The   same    phenomena  of  the  Word 
are   observed   every  time    the    same   treatment    is        use' 
used.     We  do  not  know  anything  further  than  that  this  relation 
of  sequence  obtains.     The    result  is  a  continual  coincidence 
and   nothing   more.     Its   repetition    on  the    next   occasion  is 
highly  probable,  but  we    perceive  in  the  phenomena   nothing       j 
which  makes  the  consequence  a  necessity.     In  such  cases  we 
employ  the  word  cause,  and  by  this  term  we  describe  some  one 
occurrence  which  always  precedes  some  other.     Pearson l  says  : 
"  Cause,  in  this  sense,  is  a  stage  in  the  routine  of  experience, 
and  not  one  in  a  routine  of  inherent  necessity."     The  term 
cause  is  misused  when  it  is  applied  to  phenomena  which  are 
related  by  co-existence,  or  when  it  is  applied  to  gravity  or  affinity, 
which  are  facts  simply,  not  causes  at  all. 

The  teaching  of  science  consists  in  establishing  a  point  of 
view  and  not  merely  conveying  a  knowledge  of  facts.  We 
should,  therefore,  avoid  the  misuse  of  words  like  cause  and 
effect.  When,  through  misuse  of  words  like  these,  the  rules  of 

1  Karl  Pearson,  Grammar  of  Science,  chapter  IV. 


152          INSTRUCTION  IN  THE   CLASSROOM 

the  Grammar  of  Science  are  broken,  obsession  by  false  points 
of  view  ever  afterwards  distorts  the  victim's  whole  conception 
of  the  method  of  description  and  classification  in  which  the 
study  of  science  consists.1 

Not  to  prolong  our  list,  we  may  mention  finally  the  words 
matter  and  energy.  There  is  much  difference  of  opinion  as  to 
'Matter'  tne  definition  of  these  terms.  It  is  certain,  how- 

and  ever,  that  some  of  the  current  statements  are  de- 

cidedly misleading.  For  example,  it  is  sometimes 
said  that  the  universe  is  made  up  of  matter  and  energy.  Again  we 
learn  that  matter  is  the  vehicle  of  energy.  Still  again  we  find 
the  statement  that  energy  is  the  cause 2  of  change  in  matter. 
Each  of  these  statements  suggests  an  entirely  different  relation, 
and  all  are  more  or  less  misleading.  Our  whole  knowledge 
of  the  universe  is  obtained  by  the  study  of  our  sense  im- 
pressions. In  describing  these,  we  employ  two  conceptions. 
The  idea  of  matter  gives  account  of  much  that  we  perceive. 
Since,  however,  matter  may  be  at  rest  or  in  motion,  hot  or 
cold,  electrified  or  neutral,  and  the  same  specimen  can  change 
its  state  of  motion,  or  of  electrification,  or  its  temperature,  we 
separate  these  phases  of  the  data  of  our  experience,  and  employ 
a  second  conception,  that  of  energy,  for  the  purpose  of  describ- 
ing them.  Now  we  cannot  logically  describe  one  conception 
as  the  vehicle  of  another,  any  more  than  we  can  say  that 
one  axis  in  co-ordinate  geometry  is  the  vehicle  of  the  other. 


1  It  may  be  well  to  emphasize  the  fact  that  the  discussion  of  topics 
like  those  handled  in  this  section  is  by  no  means  to  come  before  the 
pupil.  He  could  not  understand  their  import  and  would  only  be  confused. 
The  teacher  can  convey  correct  ideas  concerning  '  law '  and  '  cause,'  and 
'energy'  as  readily  as  incorrect  ones,  if  he  is  aware  of  the  danger  which 
lies  in  the  employment  of  careless  forms  of  expression,  without  openly 
discussing  the  terms  themselves. 

2  In  many  actions  the  employment  of  some  form  of  energy  is  an- 
tecedent to  chemical  change,  in  others  the  chemical  change  seems  to  be 
antecedent  to  the  production  of  some  manifestation  of  energy.  There  is 
evidently  here  no  constant  order  of  sequence.  We  have  as  frequent 
reason  for  saying  that  change  is  the  cause  of  energy  as  that  energy  is  the 
cause  of  change. 


INSTRUCTION  IN  THE   CLASSROOM         153 

The  conceptions  must  be  kept  independent,  or  they  cannot 
subserve  the  purpose  of  describing  the  complex  phenomena  of 
experience.  Matter  and  energy  are  not  parts  of  the  universe, 
but  constituents  of  our  mode  of  thinking  about  it  and  describing 
it.  Philosophically  they  are  best  classified  as  conceptions  of 
the  mind  and  not  things  of  an  objective  nature.1 


1  See  Karl  Pearson,  Grammar  of  Science,  chapter  VII.  and  Stallo, 
who  seems  to  use  the  terms  force  and  energy  as  equivalent,  Concepts 
and  Theories  of  Modern  Physics,  chapter  X.  149.  Cf.  James  Ward, 
Naturalism  and  Agnosticism,  Lecture  VI.,  passim. 

Karl  Pearson's  Grammar  of  Science  gives  an  admirably  clear  account 
of  many  of  the  matters  discussed  in  this  section,  and  will  be  found  to 
throw  a  flood  of  light  upon  the  foundations  of  scientific  thought.  The 
whole  contents  of  this  book  are  bound  to  be  a  surprise  to  the  student 
who  has  read  only  treatises  on  the  individual  sciences.  The  same  sub- 
jects, in  part,  are  treated  with  great  clearness  and  philosophic  insight  in 
the  first  volume  of  James  Ward's  Naturalism  and  Agnosticism,  chapters 
I.-VI.  The  teacher  will  also  derive  much  benefit  from  reading  Clifford's 
Seeing  and  Thinking  and  Mach's  Popular  Scientific  Lectures,  as  well 
as  Clifford's  Essays  and  Stallo's  Concepts  and  Theories  of  Modern 
Physics^  to  which  reference  has  already  been  made. 


CHAPTER  VI 

SOME    CONSTITUENTS   OF   THE    COURSE. 

THE  reader  will  have  observed  that  a  number  of  topics  usually 
treated  in  chemistry  have  not  yet  received  recognition  in  our 
discussion  of  the  subject.  Some  of  these  are  of  very  great  im- 
portance, and  some  of  them  have  a  prominence  in  chemical 
instruction  which  is  perhaps  somewhat  out  of  proportion  to 
their  intrinsic  value.  Our  first  section  naturally  treats  of  the 
atomic  theory.  This  might  perhaps  have  demanded  a  place  in 
the  chapter  on  "The  Introduction  of  the  Subject"  at  least  as 
potently  as  the  question  of  equations.  Other  topics  of  the 
same  kind  are  valency,  physical  chemistry,  and  qualitative 
analysis.  The  order  in  which  we  take  them  is  the  order  of 
their  logical  relation,  rather  than  that  of  their  importance  as 
features  in  elementary  instruction.  If  we  had  adopted  the 
latter  principle,  the  arrangement  might  have  been  different. 

I.     The  Atomic  Theory,  its  Nature  and  Place  in  Elementary 
Instruction. 

a.    The  Atomic  Theory  not  a  Fact :  —  A  theory  is  often  formed 
by  imagining  a  simple  mechanical  system,  which  would  behave 
like  some  very  complex  subject  of  experiment  in 
call  for  this      respect  to  certain  clearly  defined  features  in   the 
Theory.  phenomena  presented  by  the  latter,  and  to  these 

features  only  of  all  the  bewildering  properties  it  may  possess. 
The  atomic  theory  is  of  this  nature  :  it  professes  to  explain 
certain  features  of  chemical  change.  When  we  have  found 
that  each  compound  has  a  constant  composition,  there  is  no 
particular  necessity  for  a  theory  to  explain  a  fact  in  itself  so 


SOME   CONSTITUENTS  OF  THE   COURSE      155 

simple.  When,  however,  we  learn  that  the  compositions  of 
several  compounds  containing  the  same  constituents  are  related 
by  the  rule  of  multiple  proportions,  and  that  irregular  quanti- 
ties are  never  observed,  we  feel  a  certain  satisfaction  in  thinking 
that  if  the  constituents  were  done  up  in  definite  packets  of 
uniform  size,  such  a  rule  would  be  the  inevitable  consequence 
of  the  formation  of  several  kinds  of  compounds.  When  later 
we  reach  the  principle  of  combining  weights  (p.  75),  and  find 
that  certain  weights  may  be  assigned  to  the  elements,  which,  if 
they  have  been  correctly  chosen,  will,  in  combination  with  the 
use  of  small  multiples  when  necessary,  express  the  weight  in 
which  the  elements  enter  into  all  kinds  of  combinations,  we  feel 
an  impulse  to  suppose  that  we  are  dealing  with  materials  which 
are  constructed,  physically,  like  the  interchangeable  parts  of  a 
number  of  machines.  The  idea  suggests  itself  that  matter  is 
so  made  that,  if  we  could  reach  the  ultimate  parts  of  which  a 
quantity  of  an  element  consists,  by  simply  shutting  our  eyes 
and  taking  one  or  two  pieces  we  should  find  that  they  would 
associate  themselves  with  precision  with  other  pieces  of  other 
elements  to  produce  any  number  of  different  structures. 

We  should  note,  however,  that,  convincing  as  the  theory 
seems,  the  facts  which  it  explains  do  not  in  any  sense  consti- 
tute a  proof  that  matter  is  really  constructed  as  the  _. 
theory  demands.  An  illustration  will  make  this  not  Inevitably 
clear.  If  we  had  never  observed  wheat  or  gold  a  Factt 
close  at  hand,  and  depended  entirely  upon  the  market  quota- 
tions for  our  information  about  them,  we  should  naturally  infer 
that  wheat  was  always  done  up  in  bushels,  and  gold  in  ounces. 
Yet  the  fact  is  that  these  substances  have  no  such  structure. 
They  assume  the  forms  of  the  bushel  and  the  ounce  only  at 
the  moment  of  measurement.  So  there  might  be  imagined 
properties,  at  present  unknown  to  us,  which  directed  the  quan- 
titative selection  of  material  for  chemical  change,  and  rejected 
the  excess,  without  the  existence  of  any  permanent  segregation 
into  pieces  of  unalterable  dimensions.  The  only  bushels  and 
ounces  which  we  have  are  in  the  measuring  apparatus  and  not 


156      SOME   CONSTITUENTS  OF   THE   COURSE 

in  the  material  measured ;  so  the  only  atomic  weights  may  be 
in  the  properties  controlling  chemical  combination,  and  not  in 
the  matter  combining.1 

b.  Its  Limited  Application :  —  The  atomic  theory  has  been 
invented  because  of  the  difficulty  we  have  in  forming  any 
mental  image  of  the  complex  phenomena  of  chemical  change 
as  it  takes  place  in  large  masses  of  matter.  It  furnishes  a  very 
fortunate  suggestion  of  a  mechanism  which  would  exhibit  some 
of  these  properties. 

But  the  habit  which  chemists  have  acquired  of  speaking  in 
terms  of  the  atomic  theory  as  if  it  described  objective  realities 

has  obscured  to  some  extent  the  fact  that  it  does 
'What  the 
Theory  does     n°t  attempt  to  account  for  everything  in  chemical 

and  does  not  change.  It  explains  to  us  why  200  parts  of  mer- 
cury is  the  most  convenient  chemical  unit,  and 
describes  the  formation  of  mercuric  iodide  by  the  union  of  this 
amount  with  254  parts  of  iodine  in  terms  of  the  packet  theory. 
It  also  accounts  for  the  persistence  of  the  masses  of  the  inter- 
acting bodies,  the  only  properties  of  the  original  materials  which 
survive  chemical  change.  In  other  words,  it  explains  the 
quantitative  relations.  It  makes  no  attempt,  however,  to  pic- 
ture to  us  the  mechanism  which  would  account  for  the  disap- 
pearance of  a  shining,  liquid,  heavy,  metallic  substance,  and 
another  black,  or  perhaps  we  should  say  violet  body,  each  with 
a  definite  set  of  physical  properties,  and  the  appearance  of  a 
scarlet  solid  with  a  totally  different  array  of  properties.  That 
the  mere  placing  of  a  particle  of  mercury  very  close  to  a  par- 
ticle of  iodine,  and  in  such  a  way  that  separation  can  still  be 
effected  at  will,  should  lead  to  the  production  of  a  composite 
particle  having  properties  markedly  departing  from  the  average 
of  those  of  the  constituents  is  inconceivable.  For  the  explana- 


1  Cf.  Stallo,  loc.  cit.,  chapter  VII.  An  entirely  different  mode  of  show- 
ing that  the  laws  of  combination  might  hold,  even  if  the  same  identical 
little  pieces  of  matter  were  not  attached  and  detached  in  the  course  of 
chemical  changes,  is  suggested  by  Karl  Pearson  (loc.  cit.,  chapter  VII.  §  6). 
Cf.  also  James  Ward,  loc.  cit.,  Lectures  IV.  and  V.  passim. 


SOME   CONSTITUENTS  OF   THE   COURSE      157 

tion  of  the  complete  transformation  actually  observed,  a  much 
more  complex  theory  would  be  needed  (cf.  foot-note  to  p.  75). 
To  mention  the  atomic  theory  as  furnishing  such  an  explana- 
tion is  to  perpetrate  a  palpable  absurdity.  Even  the  youngest 
pupil  must  recognise  the  total  inadequacy  of  the  explanation, 
and  only  the  submissive  spirit  produced  by  prolonged  dog- 
matic instruction  can  prevent  the  criticism  and  rejection  of  so 
pretentious  a  claim.  The  use  of  the  theory  must  therefore 
be  confined  at  first  to  the  explanation  of  the  quantitative 
relations. 

When  valency  is  reached,  the  atomic  theory  finds  once  more 
useful  application.  Later  still,  in  college  work,  when  the  rela- 
tions of  the  constituents  of  a  complex  compound 
are  described,  the  same  theory  becomes  practically 
indispensable.  Here,  in  the  region  of  molecular  in  Later 
constitution,  it  reaches  the  zenith  of  its  success. 
But  still,  it  is  only  so  long  as  we  hold  it  to  the  role  of  a  theory 
and  restrict  its  application  to  certain  aspects  of  chemical  change 
that  it  is  of  assistance.  Nobody  thinks  that  the  molecules  are  in 
reality  at  all  like  our  graphic  formulae.  This  application  of  the 
theory  simply  helps  us  to  form  a  mental  image  of  the  gener- 
alized relations  which  subsist  between  the  facts  of  chemical 
behaviour. 

The  fact  is,  then,  that  in  elementary  chemistry  the  atomic 
theory  attempts  primarily  to  explain  only  the  properties  of  com- 
bination by  weight  and  volume,  and  it  succeeds  in  this  only 
because  it  leaves  out  of  consideration  the  multitude  of  other 
less  easily  classified  relations  which  make  the  actual  phenomena 
so  difficult  to  conceive  and  describe.  When  we  thus  relieve 
the  atoms  of  the  necessity  of  explaining  the  whole  marvel  of 
chemical  change,  they  begin  by  being  simply  counters  repre- 
senting the  combining  weights ;  and,  just  as  counters  are  not 
money,  but  have  a  numerical  value,  and  assist  in  keeping  account 
of  transfers  of  money,  so  atoms  may  be  regarded  at  first  as  pri- 
marily a  fictitious  medium  of  exchange,  in  terms  of  which  we 
chronicle  the  account-keeping  side  of  chemistry.  It  is  only 


158      SOME   CONSTITUENTS  OF  THE   COURSE 

in  the  later  application  that  the  atoms  become  more  and  more 
concrete.1 

c.  The  Place  of  the  Theory  in  Elementary  Instruction :  — 
Having  now  cleared  the  way  by  pointing  out  the  limitations  of 
Untimely  ^ie  atormc  theory,  we  are  prepared  to  take  up  the 
Employment  much-debated  question  in  regard  to  the  proper 
eoiy'  time  for,  and  manner  of  its  introduction  in  an  ele- 
mentary course.  One  would  fear  being  accused  of  uttering  a 
platitude  when  stating,  in  the  first  place,  that  the  use  of  a  theory 
is  to  explain  facts,  and  that  it  must,  therefore,  follow  the  facts  to 
be  explained,  if  it  were  not  the  most  conspicuous  feature  of  the 
situation  that  the  atomic  theory  alone,  of  all  the  theories  of 
science,  seems  to  have  gained  a  kind  of  prescriptive  right  to 
take  precedence  of  the  phenomena.  The  most  cursory  study 
of  the  text-books  and  the  methods  of  the  teachers  of  chemistry 
will  show  that  this  is  the  case  to  a  predominating  extent.  And 
yet  in  the  work  which  leads  up  to  the  noting  of  the  qualitative 
characteristics  of  chemical  change  there  is  nothing  which  the 
atomic  theory  can  explain  or  attempts  to  explain.  Not  only 
does  it  fail  to  explain  the  transmutation  of  iron  and  sulphur 
into  ferrous  sulphide ;  it  is  even  flatly  discredited  by  an  un- 
biased consideration  of  the  superficial  features  of  the  occur- 
rence. Iron  and  sulphur,  no  matter  how  finely  we  divide 
them,  and  how  closely  we  put  them  side  by  side,  always  remain 
iron  and  sulphur.  The  natural  inference  so  far,  therefore,  is 
that  the  union  must  consist  in  something  entirely  different 
from  a  juxtaposition  of  minute  fragments  which  retain  their 
identities.  If,  therefore,  we  force  the  conventional  so-called 
explanation  on  the  pupil  at  this  stage,  he  is  bound  to  see  that 
the  doctrine  is  incapable  of  immediate  assimilation  with  the 
experimental  facts,  that  it  is  thus  not  of  the  nature  of  an  expla- 
nation, and  so  he  is  driven  to  suppose  that  it  is  itself  an  inde- 


1  The  most  recent  discussion  of  the  atomic  and  molecular  theories  is 
in  Professor  Riicker's  address  before  the  British  Association.  The 
Structure  of  Matter:  NATURE,  LXIV.  (1901),  470,  or  SCIENCE  [N.  S.], 
XIV.  425- 


SOME    CONSTITUENTS   OF   THE    COURSE       159 

pendent  fact.  It  seems  to  be  unverifiable  by  experiment,  so 
he  infers  that  the  science  must  include  dogmatic  teachings 
which  are  beyond  verification.  Long-formed  habit  makes  the 
appreciation  of  oracular  statements  of  this  kind  very  keen,  and 
so  the  dogma  is  at  once  given  the  place  of  honour  in  his  esti- 
mation, and  he  starts  his  career  as  a  student  of  the  subject  with 
a  totally  false  view  of  the  science  and  of  the  scientific  method 
in  general. 

It  is  after  the  laws  of  multiple  proportions  and  combining 
weights  have  been  observed  to  hold  true  of  chemical  changes, 
that  the  opportunity  for  the  explanation  of  these  facts  by  the 
use  of  the  atomic  theory  occurs.  Its  presentation  at  any  time 
after  this  point  is  logically  justifiable.  It  is  very  helpful  in 
giving  definite  form  to  the  conception  of  combining  weights. 
It  is  not  imperatively  needed  for  the  purpose  of  furnishing  a 
concrete  basis  for  thought  and  expression  until  Avogadro's 
hypothesis  is  introduced.  It  is  exceedingly  unlikely  that,  if  the 
consequences  of  this  hypothesis  are  to  be  developed  at  all,  they 
can  be  made  clear  to  a  beginner  in  any  other  than  the  tradi- 
tional manner.  At  this  point  the  molecular  and  atomic  theories 
will  usually  be  employed  frankly,  although  Professor  Ostwald 
(in  his  Outlines  of  Inorganic  Chemistry]  has  recently  endeav- 
oured to  avoid  them  even  at  this  stage. 

The  ever-present  dangers  seem  to  be  those  of  forgetting  that 
the  atomic  theory  is  a  theory,  and  of  permitting  the  limitations 
discussed  above  to  slip  out  of  view.  There  is  also  Dangers  to  be 
a  tendency  to  treat  the  subject  too  realistically,  and  Avoided- 
as  if  the  behaviour  of  the  atoms  was  the  subject  of  direct  obser- 
vation. The  latter  tempts  us,  after  we  have  observed  the  burn- 
ing of  magnesium,  to  say,  without  more  ado,  that  the  action 
takes  place  by  the  union  of  one  atom  of  the  metal  with  one  atom 
of  oxygen.  If  the  pupil  makes  no  measurement,  we  should  tell 
him  that  weighing  gives  the  proportion  of  the  elements  in  this 
compound;  that  elaborate  experimental  investigation  has  as- 
signed 24.36  and  1 6  as  the  most  convenient  combining  weights 
of  the  elements  concerned ;  that  the  proportion  here  turns  out 


160      SOME   CONSTITUENTS  OF  THE   COURSE 

to  be  that  of  one  combining  weight  of  each  element ;  and  that 
hence,  in  terms  of  the  atomic  theory,  one  atom  of  each  element 
is  used.  Without  these  esseniial  links,  all  implied  in  the  origi- 
nal statement,  of  course,  but  incapable  of  extraction  from  it  by 
the  inexperienced  imagination  of  the  beginner,  the  pupil  cannot 
perceive  the  basis  of  our  description  of  the  action,  or  understand 
what  it  means.  [  It  would  be  better  to  avoid  the  term  atom  as 
much  as  possible  in  the  every-day  language  of  the  classroom, 
and  to  substitute  atomic  weight  *  or  combining  weight  for  it. 
These  terms  at  once  recall  the  experimental  method  which  is 
the  true  basis  of  every  statement.2 

I  remember  being  present  at  a  conference  at  which  the  sub- 
ject of  the  present  section  was  being  discussed.  The  leader 
Consequence  was  mcnne(^  to  favour  explaining  the  very  first 
of  Misuse  of  chemical  change  as  an  operation  involving  atoms, 
eory*  and  leading  the  pupil  to  think  of  everything  that 
happened  in  terms  of  the  atomic  theory  from  the  very  start. 
I  had  just  interposed  some  remarks  expressing  views  similar 
to  those  defended  here,  and  had  wound  up  by  pointing  out 
that  the  science  of  chemistry  dealt  practically  with  the  behaviour 
of  gross  matter  and  not  with  the  vagaries  of  atoms,  when  a 
young  man  near  me,  who  apparently  had  difficulty  in  restrain- 
ing his  impatience,  burst  out  with  the  exclamation,  "  If  chem- 
istry is  not  all  about  atoms,  what  is  it  about?"  He  was 
a  pupil  of  the  leader  of  the  conference  and  seemed  never  to 
have  been  led  to  realize,  that,  in  the  great  department  of 
knowledge  which  constitutes  the  science  of  chemistry,  the  com- 
plex processes  of  nature  which  it  describes,  the  magnificent 
industries  which  it  has  founded  and  still  guides,  the  services 
to  the  community  which  it  renders  in  a  thousand  applications 
of  analysis,  and  the  multitude  of  distinct  bodies  and  their  rela- 


1  For  the  definition  of  the  expression  'atomic  weight'  in  terms  of 
experiment,  see  footnote  to  p.  164. 

2  For   the   most   satisfactory   treatment   of    the  atomic    theory,   see 
ITofmann,  Introduction   to  Modern  Chemistry  (London,    1865),  chapters 
X.-XIT. ;  Ostwald,   Outlines  of  Inorganic  Chemistry  (Macmillan),  chap- 
ter VII. ;  Remsen,  Chemistry  (advanced  course),  chapter  VI. 


SOME   CONSTITUENTS  OF  THE   COURSE      l6l 

tionship  with  which  it  deals,  there  is  scarcely  ever  any  mention 
of  the  atomic  theory,  except  as  in  so  far  as  it  may  furnish  an 
occasional  figure  of  speech  in  their  discussion. 

The  elementary  chemistry  of  the  classroom  is,  or  should  be 
obtained  by  a  careful  reduction  of  the  whole  subject  to  a  smaller 
scale,  and  a  careful  elimination  of  the  parts  which  The  ^  and 

in  the  microcosm  have  become  inconspicuous  de-   Practice  of 

.  ,  Condensation 

tails.     This  process  cannot  be  carried  out  by  any  appiied  to 

one  who  is  not  a  chemist  with  a  broad  knowledge  Chemistry, 
of  the  subject  in  the  unreduced  form.  Too  many  writers  of 
text-books  have  not  the  necessary  qualifications  for  their  task. 
In  the  process  of  eliminating  all  that  can  be  left  out  in  the  most 
elementary  work,  and  in  arranging  the  remainder  with  a  view 
to  what  is  supposed  to  be  a  simple  and  pedagogically  correct 
method  of  presentation  for  the  use  of  the  beginner,  a  good  deal 
of  distortion  sometimes  occurs,  and  the  result  of  this  severe 
banting  process  is  in  danger  of  becoming  a  mere  phantom,  if 
not  a  caricature  of  its  former  self.  It  is  as  difficult  to  recognise 
the  ox  in  the  beef  extract,  even  when  the  latter  is  genuine,  as 
the  science  itself  in  some  of  the  epitomes  which  are  placed 
at  the  service  of  the  teacher.  In  theory,  the  elementary  course 
in  chemistry  should  represent  the  main  features  of  the  science  in 
petto,  and  show  it,  as  it  were,  viewed  through  the  wrong  end  of 
an  opera-glass.  When  the  reduction  has  been  carried  out  faith- 
fully, the  microcosm,  if  once  more  expanded,  should  reproduce 
in  outline  the  image  of  the  original.  It  is  to  be  feared  that  were 
this  re-enlargement  attempted  with  much  of  the  tabloid  chem- 
istry of  the  schoolroom,  a  monster  of  terrifying  and  most  un- 
natural form  would  be  hatched  forth.  It  may  be  possible  to 
introduce  the  atomic  theory  at  an  early  stage  without  causing  con- 
fusion, and  to  talk  to  beginners  of  atoms,  when  combining  weights 
are  intended,  without  obscurity,  but  I  do  not  know  any  text-book 
in  which  this  has  been  done  successfully,  and  I  could  name  many 
in  which  it  has  been  attempted  with  disastrous  results. 

In  conclusion,  and  at  the  risk  of  being  accused  of  over- 
insistence,  let  us  look  at  the  matter  from  still  another  point 

ii 


1 62      SOME    CONSTITUENTS   OF   THE   COURSE 

of  view.  If  we  reflect  upon  what  has  been  said  in  the  opening 
section  of  the  chapter  on  "The  Introduction  of  the  Subject," 
we  may  get  additional  light  upon  the  question 
Theory  and  before  us.  We  enumerated  three  distinct  char- 
chemistry  to  acteristics  of  chemistry,  which,  while  they  offer 

a  Place  in  the  impediments  at  the  beginning  of  the  pupil's  course, 
Curriculum.  .  f.  .  .  . 

at  the  same  time  constitute  the  precise  reasons  for 

introducing  a  fresh  study  and  a  new  kind  of  discipline.  There 
was  first  the  fact  that  it  accustomed  the  student  to  knowledge- 
making  with  material  objects  and  phenomena  as  the  basis  of 
this  exercise.  Atoms  are  not  material  objects  whose  presence 
and  properties  he  can  perceive  by  his  senses,  and  thus  do  not 
furnish  concrete  material  for  the  knowledge-making  process.  In 
the  second  place,  the  treatment  of  the  subject  was  to  be  induc- 
tive, and  was  to  start  from  a  large  body  of  facts,  and,  by  the 
study  of  these,  to  lead  to  the  elaboration  of  more  general  truths 
and  more  abstract  conceptions.  Now  the  atomic  theory  does 
not  constitute  a  part  of  the  fundamental  data  of  the  science.  In 
the  third  place,  the  pupil  was  to  be  taught  to  rely  upon  his  own 
powers  of  observation  and  inference,  and  to  learn  to  discount 
the  teachings  of  authority.  If  at  the  very  outset  we  state  that 
matter  is  composed  of  atoms,  we  ask  him  to  accept  on  faith 
something  which  he  cannot  observe,  and  could  never  have 
found  out  for  himself.  Instead  of  asking  him  to  exercise  his 
own  powers,  we  treat  him  to  a  dogma,  and  we  cannot  even  ren- 
der the  dose  palatable  by  furnishing  convincing  reason  for  our 
belief,  for  we  have  none.  Thus  the  teacher  who  dogmatically 
introduces  the  theory  of  atoms,  violates  every  one  of  the  condi- 
tions imposed  by  the  nature  of  the  subject,  and  proceeds  treach- 
erously to  undermine  the  foundations  of  the  very  claims  which 
have  secured  for  the  science  admission  to  the  curriculum.1 

II.     The  Treatment  of  Valency. 

When  chemistry  is  treated  in  a  mechanical  fashion  valency  is 
a  most  important  topic  since  chemical  union  is  the  subject  of  the 
1  See  also  pp.  79,  8r,  and  164,  footnotes. 


SOME   CONSTITUENTS  OF  THE   COURSE      163 

science  and,  in  this  view,  is  effected  by  the  hooking  together  of 
atoms.  The  number  of  hooks  which  each  possesses  is  naturally 

one  of  the  first  things  we  wish    to   know  about. 

Can  Valency 
When,  on  the  other  hand,  this  burlesque  mode  of  be  Explained 

treatment  is  avoided,  valency  is  still  recognised  toBe^iimers' 
as  highly  significant,  but  trouble  is  encountered,  in  trying 
to  introduce  it  at  any  early  stage,  on  account  of  the  difficulty 
of  explaining  its  experimental  basis.  I  am  inclined  to  think, 
however,  that,  if  the  way  in  which  it  arises  out  of  experimental 
work  is  made  sufficiently  clear,  there  is  no  reason  why  valency 
should  be  quarantined  as  a  thing  which  is  unteachable  without 
lapse  into  over-realistic  atom  mechanics.  It  is  certainly  not 
primarily  'the  capacity1  of  an  atom  for  holding  other  atoms  in 
combination.'  This  is  simply  its  interpretation  according  to  the 
atomic  theory,  and  ranges  it  along  with  the  other  facts  of  the 
science  in  harmony  with  the  rest  of  this  great  conception. 

Valency  arises,  of  course,  experimentally,  after  we  have  chosen 
the  values  for  our  combining  weights  which  shall  be  elected  to 
the  proud  position  of  atomic  weights,  and  this  choice,  _ 
in  its  turn,  comes  after  the  explanation  of  Avogadro's  Origin  of 
hypothesis,  the  consequences  of  which  determine  ency* 
the  choice  uniquely.  An  illustration  will  make  clear  exactly 
what  is  meant.  Take,  for  example,  the  action  of  zinc  upon 
hydrochloric  acid  (Zn  +  2HC1  -+  ZnCl2  +  H2).  Before  we 
have  settled  the  atomic  weight  of  zinc,  we  simply  find  that  32.5 
grams  of  it  displace  i  gram  of  hydrogen.  After  we  have  fixed 
the  atomic  weight  of  zinc  as  65,  that  of  hydrogen  as  i,  and 
that  of  chlorine  as  35.5,  by  analysis  and  the  application  of 
Avogadro's  hypothesis  (cf.  footnote,  p.  164),  our  measurement 
tells  us  that  65  grams  of  zinc  displaces  2  grams  of  hydrogen 
and  combines  with  7 1  grams  of  chlorine.  One  chemical  unit 
of  zinc  therefore  plays  the  part  of  two  chemical  units  of  hydro- 


1  The  word  'power,'  frequently  substituted  for  'capacity,'  in  this 
phrase  is  inadmissible.  Valency  is  not  in  any  way  a  measure  of  the 
force  with  which  atoms  are  held  together,  but  only  of  the  number  of 
atoms  that  can  be  held  by  one. 


1 64      SOME    CONSTITUENTS   OF   THE   COURSE 

gen  and  unites  with  two  chemical  units  of  chlorine.  In  conse- 
quence of  this,  we  say  that  the  chemical  unit  of  zinc  is  bivalent. 
Valency  is  thus  simply  a  consequence  of  the  choice,  amongst 
possible  combining  weights,  of  the  final  atomic  weight.  There 
is  no  new  addition  to  the  theory  of  the  subject,  no  so-called 
'  theory  of  valency '  involved. 

Valency  may  be  placed  on  a  sound  experimental  basis,  even 
before  Avogadro's  hypothesis  has  been  discussed  and  atomic 
weights  have  been  settled,  by  the  device,  which  may  have  been 
used  already  for  other  purposes,  of  stating  that  the  chemical 
unit  has  been  settled  on  grounds  to  be  discussed  later,  and  that 
its  value  in  the  case  of  zinc  is  65.  The  logical  necessities  of 
the  case  are  satisfactorily  met  by  plain  indication  of  the  experi- 
mental basis  and  perfectly  clear  delimitation  1  of  any  assumption 
which  may  have  to  be  made. 


1  The  nature  of  valency  is  so  continually  referred  to  as  an  exceedingly 
obscure  subject  that  there  must  surely  be  some  lack  of  clearness  in  the 
explanation  commonly  given.  We  may  be  pardoned  therefore  for  a 
brief  statement,  in  harmony  with  the  above  paragraph,  of  its  nature  and 
origin. 

If  gases  had  no  properties  which  suggested  Avogadro's  hypothesis, 
how  would  the  composition  of  chemical  compounds  be  represented  by 
formulae,  and  what  would  be  the  values  of  the  atomic  weights  (and  there- 
fore of  the  symbols)  ?  We  should  find  by  experiment  the  composition  of 
aluminium  chloride  to  be  AIC\  (Al  =  9  instead  of  Al  =  27),  of  zinc  chlo- 
ride to  be  ZnCl  (Zn  =  32.5  instead  of  Zn  =  65),  of  carbon  tetrachloride 
to  be  CC\  (C  —  3  instead  of  C  =  12),  of  arsenious  chloride  to  be  AsCl 
(As  —  25  instead  of  As  =  75),  and  arsenic  chloride  to  be^Cl  (As  =  15 
instead  of  As  =  75),  and  every  chemical  unit  would  have  the 
same  valency,  that  is,  would  be  univalent.  Where  there  were  two 
different  units  used  by  one  element,  as  in  the  case  of  arsenic,  heavy 
type  might  be  made  use  of  for  the  larger  equivalent,  or  formulae  like 
as^Cl  and  as$C\  (as  =  5)  might  be  employed. 

Now  what  effect  has  the  application  of  Avogadro's  hypothesis  upon 
this  ?  We  weigh  equal  volumes  of  the  vapours  of  all  the  compounds  of 
every  element,  so  far  as  we  can  volatilize  them,  and  record  the  weights  of 
volumes  equal  to  that  occupied  by  two  grams  of  hydrogen  (or  rather  32 
grams  of  oxygen.  If  O  =  16,  the  volume  is  22.39  litres,  —  the  gram-molec- 
ular volume)  under  the  same  conditions.  On  inspecting  the  quantities 
of  the  constituent  elements  found  by  analysis  in  these  weights  (now  molec- 
ular weights)  of  all  the  compounds,  we  find  that  no  compound  of  alu- 
minium contains  less  than  27  grams  of  the  element  in  the  molecular 


SOME   CONSTITUENTS  OF  THE   COURSE      165 


III.     Use  of  the  Results  of  Physico-chemical  Investigation. 

Some  of  our  works  on  physical  chemistry  have  given  so  mathe- 
matical an  aspect  to  this  subject  that  the  ordinary  chemist  has 


weight,  no  compound  of  zinc  less  than  65,  and  no  compound  of  arsenic 
less  than  75,  and  that  when  the  numbers  are  larger  they  are  always 
integral  multiples  of  these  numbers.  If  we  retain  our  old  equivalents, 
but  adapt  our  formulae  so  that  they  represent  molecular  weights,  we  shall 
find  Alz  (Al—^),  or  some  multiple  of  this,  in  every  formula  of  com- 
pounds containing  aluminium  and  Zw2  (Zw  =  32.5)  and  C4  (C  =  3)  in 
every  formula  of  the  compounds  of  zinc  and  carbon.  The  chlorides 
would  therefore  be  AlzCl&  ZnzC/3,  and  (74CV4.  To  avoid  this  complica- 
tion, we  write  Al  =  Al&  (=27),  getting  the  formula  A1C13  and  we  adjust 
the  other  cases  similarly. 

Thus  in  applying  Avogadro's  hypothesis,  we  have  ourselves,  in  a 
manner,  brought  valency  about.  It  is  not  a  complication  but  a  simpli- 
fication of  our  way  of  representing  chemical  composition,  particularly 
in  the  case  of  elements  having  more  than  one  equivalent.  It  has 
the  additional  advantage  that,  when  the  atomic  theory  is  introduced, 
it  then  suggests  the  consideration  of  different  elements  as  having 
various  capacities  for  holding  chemical  units  of  other  elements,  and 
leads  to  the  use  of  graphic  formulas.  The  inestimable  value  of  substitu- 
ting a  formula  like  CC14 

Cl 

i 

Cl  -  C  -  Cl, 

I 

Cl 

for  C4C14  is  seen  in  the  marvellous  results  which  the  study  of  organic 
compounds  has  yielded.  to 

Experimentally,  valency  is  the  number  of  grams  of  hydrogen  (or  the 
multiple  of  8  grams  of  oxygen)  which  are  displaced  by  or  combine  with 
one  gram-atomic  weight  of  the  element,  when  the  gram-atomic  weight  is 
the  least  quantity  found  in  the  gram-molecular  weights  in  all  compounds 
of  the  element. 

It  may  not  be  out  of  place  to  add  that  experimentally  the  atomic 
weight  of  an  element  is  in  general  the  smallest  weight  of  the  element 
which  is  found  in  the  gram-molecule  of  any  compound  containing  the 
element.  The  larger  weights  of  the  same  element  found  in  gram-mole- 
cules of  many  compounds  are  always  integral  multiples  (in  accordance 
with  the  principles  of  combining  weights  and  multiple  proportions)  of 
this  smallest  weight.  If,  as  may  happen  in  rare  cases,  they  are  not  in- 
tegral multiples,  a  molecule  containing  one  atom  of  the  element  has  not 
been  encountered,  and  the  greatest  common  measure  of  the  weights 


1 66      SOME   CONSTITUENTS   OF  THE   COURSE 

been  inclined  to  give  it  a  wide  berth.  It  is  very  certain  that 
this  side  of  physical  chemistry  has  no  prospect  of  admission  to 

the  school  course,  and  may  possibly  not  have  been 
Teacher!  if  not included  in  the  training  of  the  teacher.  Its  terrify- 
to  the  Pupil,  ing  aspect,  however,  should  not  prevent  us  from 

recognising  that  many  of  its  results  are  of  the  great- 
est interest  and  importance  in  connection  with  the  study  of 
the  most  elementary  chemistry,  and  that  we  are  also  at  liberty 
to  help  ourselves  to  the  conclusions  and  leave  the  more  theo- 
retical portions  untouched,  if  we  so  desire.  Perhaps  the  most 
important  use  of  these  results  is  in  the  general  influence  which 
they  will  have  on  the  teacher's  point  of  view  in  all  his  instruction, 
if  he  keeps  them  prominently  in  mind,  rather  than  in  the  extent 
to  which  they  may  be  expressly  imparted  to  the  pupil.  Many 
teachers,  however,  are  even  in  favour  of  teaching  some  of  the 
facts  and  theories  of  physical  chemistry  when  occasion  offers, 
and  when  there  seems  to  be  a  prospect  that  they  will  really 
assist  the  pupil  without  putting  upon  him  any  fresh  burden. 
There  are  certainly  some  parts  of  general  chemistry  in  which 
this  would  seem  to  be  possible. 


found  is  taken  as  the  atomic  weight.  This  smallest  weight  passes  un- 
divided from  compound  to  compound  as  far  as  chemical  experiment  can 
discover.  Whether  it  is  incapable  of  subdivision  is  another  question. 
In  all  probability  it  is.  For  one  thing  we  cannot  conceive  of  a  piece  of 
rtfetter  incapable  of  subdivision.  Then,  too,  J.  J.  Thomson's  work  (see 
his  very  interesting  resume  in  an  article  on  Bodies  Smaller  than  Atoms, 
POPULAR  SCIENCE  MONTHLY,  August,  1901)  seems  to  have  shown  the 
actual  existence  under  certain  conditions  of  particles  much  smaller  than 
the  chemist's  atomic  quantities.  The  atomic  weight  is  not  that  of  the 
smallest  particle  that  exists,  but  is  simply  the  smallest  subdivision  of 
which  there  is  chemical  evidence.  It  will  perhaps  lead  to  clearness  if  the 
idea  of  a  chemical  atom  being  a  round  indivisible  mass  is  given  up,  and 
there  is  substituted  for  it  the  idea  of  a  bunch  of  smaller  fragments 
which  moves  as  a  whole  through  chemical  transformations. 

Passing  over  from  the  atomic  weight  of  experiment  to  the  atom  of 
theory,  we  consider  the  latter  a  chemical  unit,  and  not  necessarily  a 
structural  unit,  certainly  not  the  smallest  particle  that  can  be  conceived 
(an  absurd  phrase).  It  is  the  smallest  mass  of  a  particular  element  of 
which  we  have  chemical  knowledge. 


SOME   CONSTITUENTS   OF   THE   COURSE      1 6; 

Most  of  the  recent  elementary  books  for  secondary  schools 
seem  to  pay  some  attention  to  the  experimental  side  of  osmotic 
pressure,  and  of  freezing  point  and  boiling  point    Kg  Rejmlts  ^ 
phenomena.    These  subjects  form  one  of  the  links   capable  of 
between  chemistry  and  physics  on  the  one  hand,  and  APPllcatlon' 
between  these  two  sciences  and  physiology  on  the  other,  and  on 
account  of  the  important  strategic  position  which   osmotic  Phe- 
they  occupy,  it  would  seem  that  any  attention  they    nomena- 
may  receive  can  be  fully  justified. 

The  decomposition  of  electrolytes  by  electricity  is  illustrated 
in  several  chemical  experiments  which  are  never  omitted  from 

any  course.     It  seems  not  unnatural,  therefore,  that 

.  Electrolysis, 

some    explanation    of  the  phenomenon  should  be 

given.  The  electrolysis  of  dilute  sulphuric  acid  cannot  be  called 
a  decomposition  of  water  by  electricity,  unless  the  electrolysis 
of  a  solution  of  potassium  nitrate  is  to  be  described  in  the  same 
way.  The  statement  leaves  too  much  out  of  account.  The 
fact,  for  example,  that  pure  water  and  dry  hydrogen  chloride,  or 
dry  potassium  nitrate,  separately,  are  practically  non-conductors, 
and  are  not  affected  by  the  current,  shows  that  solution  is 
something  more  than  a  mere  mixture  of  the  two.  Perhaps 
carefully  prepared  demonstration  experiments,  with  a  limited 
amount  of  explanation,  will  be  found  to  give  more  insight  into 
this  matter  than  long  discussion  could  do,  and  effect  a  great 
saving  in  time.  The  drifting  of  the  ions  through  the  liquid, 
for  example,  can  be  shown  in  several  ways.1  The  formation  of 
the  ions  can  be  observed  when  cupric  bromide  (cf.  Richard's 
Harvard  Outline  of  Admission  Requirements,  31),  whose  mole- 
cules are  deep  brown  or  black,  is  dissolved  in  water.  As  the 


1  It  is  so  important  that  the  teacher,  at  least,  should  be  thoroughly 
familiar  with  this  subject,  that  he  should  not  fail  to  assist  his  own 
study  of  it  by  trying  experiments  for  himself.  A  number  of  admirably 
devised  experiments,  most  of  which  are  easy  to  carry  out,  are  fully  de- 
scribed by  A.  A.  Noyes  in  a  most  instructive  paper  (JOURNAL  OF  THE 
AMERICAN  CHEMICAL  SOCIETY,  XXII  ( 1900),  726 :  reprinted  in  the  ZEIT. 
FUR  PHYSIKAL.  CHEM.  XXXVI.  i).  Their  performance  will  throw  a  flood 
of  light  on  the  whole  subject  for  any  one  who  is  not  already  familiar  with  it. 


1 68      SOME   CONSTITUENTS   OF   THE   COURSE 

liquid  is  diluted,  the  dissociation  of  the  molecules  leads  to  the 
change  of  the  brown  colour  of  the  latter  to  the  blue  colour 
characteristic  of  the  copper  ions. 

Two  additional  reasons  for  some  attention  to  this  subject 
readily  occur  to  us.  Its  relation  to  physics,  and  the  light  which 
the  chemical  aspect  of  the  matter  throws  on  the  knowledge  the 
pupil  has  already  gained  in  the  physical  laboratory,  suggest 
the  closer  inter-relating  of  the  chemical  and  physical  views  of 
the  same  phenomena  by  means  of  the  theory  which  explains 
both.  Then,  too,  the  most  startling  recent  improvements  in 
the  chemical  industries  have  been  in  the  direction  of  the  em- 
ployment of  electricity  for  many  purposes.  Many  manufactures, 
formerly  carried  out  in  other  ways,  are  already,  or  are  rapidly 
becoming,  largely  electrolytic.  The  preparation  of  aluminium, 
alkalies,  bleaching  agents,  and  chlorates  are  examples  of  this. 
We  cannot  now  teach  chemistry  and  avoid  frequent  mention 
of  electrolytic  operations,  and  we  cannot  well  make  these 
operations  intelligible  without  some  explanation  of  the  theory. 

Double  decomposition  is  an  old  subject.  So  familiar  is  it 
that  we  do  not  always  realize  that  it  is  after  all  rather  remark- 
able. If  we  cause  two  salts  to  interact  by  heating  them,  the 
chances  are  that  a  most  complex  action  takes  place.  When  we 
mix  their  solutions  the  action  is  almost  always  simplicity  itself. 
The  solvent,  far  from  being  a  mere  bystander,  has  control  of,  and 
directs  the  action,  so  that  it  takes  place  rapidly  and  consists  in 
a  neat  exchange  of  certain  groups.  Some  explanation  of  this 
would  certainly  seem  to  be  not  out  of  place.1 

The  treatment  of  acids,  bases,  and  salts  is  a  difficult  problem 
in  chemistry.  It  is  difficult  even  to  define  the  terms  (cf.  Til- 
Acids,  Bases,  den,  Hints  on  the  Teaching  of  Elementary  Chem- 
and  salts.  '  istry^  66-68).  To  define  a  salt,  for  example,  as 
a  substance  which  is  made  in  such  and  such  a  way,  is  to  shirk 
the  task  of  defining  it  altogether.  We  shall  probably  have  to 


1  In  this  connection,  however,  see  the  work  of  Kahlenberg,  JOURNAL 
OF  PHYSICAL  CHEMISTRY,  V.  (1901),  339-392,  or  abstract  in  NATURE, 
LXV.  ( 1902),  305. 


SOME   CONSTITUENTS  OF   THE   COURSE      169 

say  that  a  salt  is  a  substance  which  enters  into  double  decompo- 
sition readily  and  whose  solution  is  an  electrolyte.  An  acid  will 
then  be  a  salt  of  hydrogen,  and  a  base  an  hydroxyl  salt.  The 
theory  of  ionization  throws  a  flood  of  light  on  the  behaviour  of 
these  substances  (see,  for  example,  "neutralization,"  in  any 
recent  work,  on  theoretical  chemistry,  such  as  Dobbin  &  Walker's 
Chemical  Theory  for  Beginners,  chapter  XIX.). 

In  the  battery  we  have  again  a  collection  of  phenomena  which 
are  as  interesting  to  the  chemist  as  to  the  physicist.     The  duty 

of  furnishing  correlation  between  the  different  sub- 

-          ,          .....  .  ,          The  Battery. 

jects  of  study,  which   is  imperative  in  secondary 

school-work,  suggests  again  the  desirability  of  some  use  of  the 
theory  of  ionization.  This  subject,  too,  is  closely  related  to 
chemistry  on  account  of  the  way  in  which  the  electro-motive 
force  produced  by  various  combinations  forms  a  numerical 
measure  of  the  intensity  of  chemical  action  taking  place  in  the 
cell.1  The  order  of  the  elements  according  to  the  electro- 
motive series  (p.  202)  has  many  applications  in  chemistry. 

Chemical  equilibrium  cannot  be  counted  amongst  the  new 
developments  of  theoretical  chemistry,  for  its  beginnings  were 
coeval  with  the  discovery  of  oxygen,  and  its  prin-  chemical 
ciples  were  clearly  understood  forty  years  ago  or  Equilibrium, 
more.  A  strange  reluctance,  however,  has  been  shown  in 
regard  to  the  recognition  of  its  laws,  both  by  investigators  and 
instructors  in  chemistry.  The  blunders  which  have  been 
made  through  failure  to  pay  attention  to  them  are  only  too 
familiar.  The  importance  of  these  principles  in  explaining 
many  of  the  commonest  chemical  changes  may  well  awaken 
surprise  at  this  strange  neglect.  The  class  of  actions  in  which 
they  find  their  chief  application,  and  which  must  be  misunder- 


1  Liipke,  in  his  Elements  of  Electro-Chemistry  (Lippincott),  describes 
and  figures  a  large  number  of  experiments  illustrating  this  subject,  and 
this  feature  of  his  book  makes  it  most  interesting  and  instructive  to  the 
reader  who  has  not  himself  any  experimental  acquaintance  with  electro- 
chemical phenomena.  A  series  of  experiments  in  the  same  subject  is 
described  by  Dr.  Lash  Miller  in  the  JOURNAL  OF  PHYSICAL  CHEMISTRY, 
IV.  599. 


I/O      SOME   CONSTITUENTS   OF   THE    COURSE 

stood  without  recourse  to  them,  namely,  reversible  actions,  form 
a  majority  of  the  changes  which  the  pupil  encounters  in  elemen- 
tary chemistry.  The  contrary  statement,  which  one  so  often 
sees,  is  so  palpably  incorrect  that  one  can  but  wonder  what  limi- 
tation the  author  was  thinking  of  when  he  made  it.  The  Brin 
method  of  preparing  oxygen  (cf.  Newth,  Inorganic  Chemistry, 
162)  by  means  of  barium  peroxide  and  the  chemical  decom- 
position of  mercuric  oxide  furnish  examples  at  the  very  outset. 
Most  of  the  chief  changes  at  the  beginning  of  the  course  are 
reversible,  and  actions  of  this  class  predominate  more  and  more 
as  the  course  progresses.  Whether  it  is  judicious  to  point  this 
out  to  the  pupil,  or  to  discuss  the  consequences  of  the  fact,  may 
be  matter  for  discussion.  But  there  is  no  question  that  if  the 
teacher  is  not  familiar  with  this  fact,  and  with  the  whole  subject, 
he  is  likely  to  fall  into  egregious  blunders,  such  as  stating  that 
sulphuric  acid  is  stronger  than  nitric  acid,  and  enunciating 
quasi-principles  of  a  misleading  kind,  like  the  so-called  ( princi- 
ples '  of  precipitation  and  volatilization.  Almost  the  only  way 
to  get  clear  ideas  on  this  subject  is  to  read  the  treatment  of  it  in 
several  different  books,  and  to  make  some  experiments  illustrat- 
ing the  principle  of  chemical  equilibrium  for  one's, self.  An 
admirable  series  of  experiments,  which,  for  the  most  part, 
may  be  performed  with  simple  apparatus,  is  described  by  Dr. 
Lash  Miller.1 

On  the  whole,  perhaps,  after  this  discussion  of  some  of  the 
bearing  of  physical  chemistry  upon  elementary  chemistry,  it 

may  be  a  question  whether,  in  the  average  course, 
Conclusions.      ...„,,        ,  r  J  .  , 

time  will  be  found  for  anything  more  than  a  touch 

of  the  subject  here  and  there.  The  conclusion  is  inevitable, 
however,  that  the  teacher  himself  must  be  thoroughly  familiar 
with  the  results  of  physical  chemistry  and  its  application  to 

1  Lash  Miller,  Experiments  Illustrating  Chemical  Equilibrium.  JOUR- 
NAL OF  THE  AMERICAN  CHEMICAL  SOCIETY,  XXII.  (1900),  291.  For 
a  simple  account  of  the  subject,  see  Carnegie's  Law  and  Theory  in 
Chemistry  (Longmans),  chapter  VII.  Cf.  references  to  chapters  in  Muir 
and  Carnegie's  Practical  Chemistry,  dealing  with  this  subject,  footnote 
to  p.  216. 


V 

SOME   CONSTITUENTS  OF  THE   COJI&9E      1 71 

ordinary  chemical  phenomena,  if  the  instruction  he  gives  is  to 
be  thoroughly  sound.  A  knowledge  of  this  subject  is  one  of  the 
most  indispensable  parts  of  the  equipment  of  the  teacher  of 
general  chemistry,  whether  in  school  or  college.  Whatever  ideas 
along  this  line  may  be  communicated  to  the  pupils  will  certainly 
be  given  in  a  very  elementary  fashion,  and  will  be  made 
thoroughly  concrete  by  careful  experimental  illustration.  In 
this  way  the  keenest  interest  may  be  awakened.  The  theories 
will  not  be  given  for  their  own  sake  as  separate  topics,  but 
strictly  in  explanation  of  phenomena  that  have  been  encoun- 
tered, and  only  so  far  as  they  simplify  and  explain  these 
phenomena.  The  teacher  who  has  not  had  an  opportunity  of 
studying  the  subject,  however,  would  do  well  to  omit  it  from 
his  instruction  entirely,  as  there  is  nothing  more  dull  and  valu- 
less  than  a  theory  which  is  not  lucidly  explained  and  adequately 
enforced  by  'pat'  application  and  experimental  illustration. 


IV.    Shall  Qualitative  Analysis  be  Included,  and  if  so  in  "What 

Form  ? 

REFERENCES. 

Armstrong,  H.  E.  Presidential  Address  before  the  Chemical  Society 
of  London.  JOURNAL  OF  THE  SOCIETY,  LXV.  (1894),  361.  Reprinted 
in  part,  NATURE,  L.  211. 

Brace,  Geo.  M.  An  Article  on  Qualitative  Analysis.  THE  SCIENCE 
TEACHER  (New  York),  II.  173  (March,  1899). 

There  is  perhaps  no  question  in  connection  with  chemistry 
as  a  study  in  the  secondary  school  which  has  called  forth  opin- 
ions so  sharply  opposed  to  one  another  as  this.  The  head  of 
the  department  in  one  of  our  State  Universities  says :  "  If  it  is 
advisable  to  have  lecture  and  recitation  work,  let  it  be  at  the 
end  of  the  course,  and  have  the  two  earlier  terms  taken  up  with 
qualitative  analysis.  ...  If  the  fortunate  state  of  affairs  exists 
that  physics  precedes  the  subject  of  chemistry,  I  think  the 
lecture  work  as  such  is  of  little  importance."  This  appears  to 


1/2      SOME   CONSTITUENTS   OF   THE   COURSE 

suggest  distinctly  that  even  classroom  work  in  general  chem- 
istry may  be  dispensed  with,  under  certain  conditions,  and  that 
the  whole  introductory  course  may  consist  in  qualitative  analysis. 
That,  on  the  other  hand,  analysis  should  be  excluded  entirely  is  a 
view  expressed  with  equal  definiteness  by  a  large  number  of  com- 
mittees and  single  authorities.  What  the  argument  in  favour  of 
making  qualitative  analysis  the  first  and  almost  exclusive  subject 
of  instruction  may  be,  it  would  be  difficult  to  say.  The  statements 
supporting  this  view  seem  always  to  be  of  the  nature  of  obiter 
dicta.  The  fact  that  analysis  must  at  best  give  but  a  restricted 
knowledge  of  chemistry  is  so  obvious  that  those  who  hold  this 
opinion  must  do  so  either  from  lack  of  reflection,  or  on 
account  of  the  influence  of  tradition,  or  perhaps  they  hold 
their  belief  simply  quia  absurdum  est.  Leaving  this  extreme 
view  out  of  consideration,  however,  there  are  strong  arguments 
presented  by  both  parties,  and  we  shall  attempt  to'  consider 
both  sides.  •  It  is  assumed,  of  course,  that,  in  what  follows,  by 
qualitative  analysis  we  mean  the  ordinary  treatment  which 
seems  almost  invariably  to  begin  with  the  tests  for  the  '  metals  ' 
and  to  confine  itself  for  the  most  part  to  wet  reactions. 

a.  Arguments  in  Favour  of  Qualitative  Analysis :  —  There  is, 
in  the  first  place,  the  consideration  that  the  school  course  may 
in  its  absence  do  little  towards  suggesting  the  variety  of  topics 
which  is  studied  under  the  name  of  chemistry.  The  introduc- 
tion of  analysis  tends  to  give  a  somewhat  more  complete  view 
of  the  science  by  presenting  another  aspect  of  it. 

It  furnishes  an  excellent  training  in  observation.  Even  if  we 
admit  that  the  phenomena  of  precipitation  are  not  in  themselves 
EasyObserva-  exceedingly  important,  the  facility  with  which  they 
tion-  lend  themselves  to  study  by  young  students  gives 

them  a  certain  value.  This  argument  is  extremely  instructive, 
for  the  satisfaction  with  which  this  sort  of  observation  is  made 
depends  upon  the  limitations  which  the  selection  of  phenomena 
useful  for  analysis  has  imposed.  The  possibilities  are  strictly 
limited  in  advance.  This  assimilates  the  work  to  that  in  Latin 
and  mathematics,  in  which  the  pupil  has  become  accustomed 


SOME   CONSTITUENTS   OF  THE   COURSE      173 

to  similar  guidance,  and  he  welcomes  the  opportunity  to  study 
something  which  has  similar  characteristics. 

The  work  exercises  the  reasoning  powers  and  furnishes 
material  for  simple  and  sure  inductions. 

Analysis  furnishes  a  review  of  certain  parts  of  the  subject 
which  have  been  studied  before,  and  thus  assists  in  crystallizing 
the  pupil's  ideas. 

The  properties  of  the  substances  encountered  may  be  studied 
in  connection  with  the  building-up  of  the  analytical  scheme,  in 
such  a  way  that  genuine  additions  are  made  to  the  pupils' 
knowledge  of  chemistry  and  the  bald  enumeration  of  precipi- 
tates and  colours  is  avoided. 

Finally,  it  is  well  known  that  analysis  is  a  subject  capable  of 
practical  application.  There  is  just  a  touch  of  something  use- 
ful about  it  which  awakens  interest  on  the  part  of  A ,  Practi. 
the  pupils,  and  inclines  parents  and  outsiders  to  cal '  Subject. 
approve  its  inclusion  in  the  high  school  curriculum.  Of  course 
this  rests  on  the  mistaken  notion  so  commonly  held  that  chem- 
istry consists  in  analysing  things,  and  that  the  scientific  chemist 
spends  his  time  in  examining  groceries  for  adulterations  and 
advising  his  neighbours  in  regard  to  the  purity  of  their  drinking 
waters.  But  it  none  the  less  creates  a  feeling  of  sympathy  with 
the  work  of  the  school  which  has  a  value  of  its  own.  The  in- 
terest of  the  pupil  is  natural,  for,  although  the  fact  that  silver 
chloride  dissolves  in  ammonium  hydroxide,  while  lead  chloride 
does  not,  possesses  no  native  interest  whatever,  the  suggestion 
that  this  can  be  used  for  distinguishing  the  substances,  or  as- 
certaining the  presence  of  lead  or  silver,  gives  it  a  powerful 
derived  interest  and  awakens  the  attention  of  the  scholar  at 
once. 

b.  Arguments  against  Qualitative  Analysis :  —  There  may 
be  some  arguments  against  qualitative  analysis  in  any  and  every 
form.  There  are  certainly  strong  arguments  against  some  types 
of  instruction  in  it,  especially  those  of  a  mechanical  kind.  We 
shall  assume,  however,  for  the  most  part,  that  the  topic  in  its 
best  and  most  rational  form  is  alone  to  be  considered,  and  that 


1/4      SOME   CONSTITUENTS   OF   THE   COURSE 

an  inadequate  basis  in  knowledge  of  the  facts  and  theories  of 
the  science  is  the  chief  defect  from  which  the  instruction 
suffers. 

To  the  first  of  the  arguments  just  given  it  is  replied  that 
chemistry  as  a  science  has  nothing  to  do  with  analysis. 
Analysis  is  an  application  of  chemistry  and  an  art  practised 
with  commercial  ends  in  view,  or  a  tool  used  in  the  prosecu- 
tion of  strictly  scientific  work.  A  little  of  it  may  enlarge  the 
ideas  of  the  pupil,  but  a  greater  amount  must  have  a  decidedly 
narrowing  influence. 

The  strongest  argument  in  favour  of  analysis  is  certainly  that 
which  points  out  the  practice  it  gives  in  observation,  guarded 

by  such  restrictions  that  complete  and  satisfactory 
The  *  Obscr- 

vationArgu-  study  is  within  the  powers  of  beginners.  The  inter- 
ment, ence  from  this,  however,  is  that  other  parts  of  the 
subject  should  be  systematized  in  the  same  way,  in  order  that 
gaining  a  fuller  and  more  complete  knowledge  of  them  may  be 
put  within  the  reach  of  the  student  of  the  elements.  A  system- 
atic yet  simple  arrangement  of  certain  facts  has  been  made  for 
the  purpose  of  analysis ;  an  equally  simple  and  systematic 
working  out  of  all  aspects  of  the  subject  should  be  made  for 
the  purpose  of  instruction.  The  commercial  impulse  has 
caused  the  former  development.  The  teacher  does  not  yet 
seem  to  have  learned  the  lesson  which  this  plainly  inculcates, 
and,  instead  of  imitating  the  principle  and  applying  it  to  the 
whole  science,  he  has  simply  borrowed  the  fragment  which  the 
analyst  has  worked  out  for  his  own  purposes,  and  saved  himself 
much  trouble  by  making  up  from  it  a  large  part  of  his  course. 
There  is  an  obvious  risk  that  too  much  system  may  lead  to 
mechanical  work,  but  it  certainly  would  seem  that  some  im- 
provement of  this  nature  might  be  made  without  trespass  on 
the  zone  of  danger. 

There  is  no  question  that  analysis  furnishes  good  exercise  in 
reasoning,  at  least  when  it  is  taught  in  a  rational  manner  and 
not  by  the  mechanical  use  of  tables.  Mr.  Brace,  in  the  paper 
referred  to  at  the  head  of  this  section,  explains  in  an  admirable 


SOME   CONSTITUENTS  OF   THE   COURSE      175 

way  how  the  best  use  may  be  made  of  its  aptitude  for  cultivating 
the  inductive  powers.     As  the  study  of  the  science  progresses, 

a  record  may  be  made  of  the  solubility  or  insolubility 

The  '  Exer- 
of  each  substance,  and  in  the  latter  case   of  the   ciseinRea- 


colour  and  other  properties  of  the  precipitate. 
When  the  table  has  been  completed,  the  pupils 
themselves  can  pick  out  a  method  of  analysis.  They  note,  for 
example,  that  three  chlorides  only  are  insoluble,  and  that  there- 
fore the  addition  of  hydrochloric  acid  will  lead  to  the  recogni- 
tion of  the  presence  of  one  of  the  metals  concerned.  With  but 
little  assistance  from  the  teacher  or  book  they  may  be  led  to 
work  out  a  complete  system  of  analysis  applicable  to  simple 
cases.  There  is,  as  we  have  said,  no  question  of  the  rational 
exercise  which  this  procedure  gives,  but  we  may  be  pardoned 
for  asking  what  the  subject  is  on  which  the  reasoning  is  being 
expended.  It  is  the  solubility  or  insolubility  of  a  large  number 
of  bodies.  Now  this  question  is  of  but  slight  interest  to  the 
chemist  as  a  chemist,  for  so  far  we  have  not  been  able  to 
explain  most  of  the  eccentricities  of  solubility.  This  sort  of 
study  puts  calcium  chloride  and  calcium  fluoride  in  diametri- 
cally opposite  classes.  It  assimilates  arsenic  and  tin,  nitrates 
and  acetates. 

Suppose  that  after  a  complete  study  of  this  had  been  made, 
the  class  were  next  invited  to  distinguish  sticky  substances  from 
brittle  ones.  Glue  and  phosphoric  acid  would  adjust  them- 
selves in  one  group,  while  salt  and  napthalene  (moth  balls) 
would  find  themselves  accommodated  in  another.  Or  suppose 
that  substances  were  classified  by  their  colours,  iodine  and  potas- 
sium iodide  would  part  company  at  once,  and  sulphur  and  sul- 
phuric acid  would  know  each  other  no  more.  In  the  same  way, 
liquids  might  be  distinguished  from  the  solids.  Mercury  and 
copper  would  be  no  longer  classed  together  as  metals,  and  in  this 
remarkable  course  ice  and  water  would  belong  to  different  groups. 
Similarly,  if  the  year  was  not  yet  exhausted,  odours  and  specific 
gravities  might  afford  opportunity  for  careful  observation  and  nice 
discrimination.  Devising  systems  of  analysis  based  on  these  facts, 


176      SOME   CONSTITUENTS  OF  THE   COURSE 

and  using  them,  would  unquestionably  furnish  admirable  exercise 
for  the  reasoning  powers.  The  fact  is  that  there  are  a  great 
many  ways  of  making  hodgepodge  of  the  chemical  relations  of 
substances  by  classification  according  to  physical  properties, 
but  the  study  of  chemistry  itself  cannot  possibly  be  assisted  by 
anything  which  makes  havoc  of  chemical  similarities,  no  matter 
how  admirable  the  exercise  it  may  furnish  for  the  reasoning 
faculties. 

The  reasoning  of  analysis,  that  by  which  we  distinguish  salts 
of  silver,  lead,  and  mercury,  for  example,  is  exactly  like  that  by 
which,  in  whist,  we  infer  the  contents  of  our  neighbour's  hand. 
Whist  might  with  advantage  be  substituted  for  qualitative  analy- 
sis, so  far  as  training  of  the  reasoning  powers  goes.  The  mere 
use  of  chemical  bodies  and  chemical  language  in  a  study  does 
not  make  it,  ip so  facto,  chemistry.  The  valid  reasons  for  study- 
ing qualitative  analysis,  without  a  foundation  far  broader  than 
any  fraction  of  a  year's  work  can  give,  amount  to  showing  that 
it  gives  good  discipline,  whether  it  contains  any  chemistry  or 
not,  and  that,  while  being  administered  to  the  pupil,  it  may  also 
be  so  liberally  basted  with  a  chemical  sauce  as  to  become  a 
good  imitation  of  a  part  of  the  science  itself.  Whist  could  be 
enriched  by  incorporating  with  it  some  study  of  the  chemistry 
of  cellulose  and  black  and  red  ink,  but  this  would  not  greatly 
advance  its  claims  to  inclusion  in  a  course  in  the  science 
intended  to  be  systematic. 

The  argument  that  analysis  may  be  employed  to  furnish  a 
review  of  the  previously  acquired  knowledge  of  the  science  is 
true  to  a  limited  extent  only.  There  are  other  ways  of  effecting 
this  review  which  cover  the  ground  much  more  completely. 

The  final  argument l  that  the  analysis  of  the  high  school  has 


1  There  is  still  another  consideration  which  affects  some  schools  more 
than  others,  and  some  pupils  in  all  schools.  It  concerns  the  pupils  who 
are  preparing  for  college.  If  some  schools  give  much  analysis,  some 
little,  and  others  none,  some  much  general  chemistry,  some  little,  and 
others  perhaps  almost  none,  the  various  pupils  from  these  schools  can- 
not possibly  be  provided  by  any  college  with  a  fit  course  in  continuation 
of  their  previous  work.  Only  those  who  have  devoted  a  year  to  general 


SOME   CONSTITUENTS  OF   THE   COURSE      177 

a  possible  practical  application,  and  teaches  something  useful, 
is  plausible,  but  will  hardly  bear  examination.  In  after-life  the 
graduate  of  the  high  school  hires  an  analyst  if  he  ^^^3^ 

wishes  any  work  of  this  nature  to  be  done.     If  he    'Practical' 

Subject 
tries  his  own  hand  at  it,  he  will  quickly  discover 

that  the  course  given  in  the  high  school  is  of  almost  no  assist- 
ance in  the  solution  of  any  practical  problem.  The  subject 
is  far  too  difficult  to  be  treated  adequately  in  a  part  of  an  ele- 
mentary course.  The  fact  is  that  the  pupil  whose  time  has 
been  taken  up  with  analysis  will  only  begin  to  discover  after 
graduation  the  utter  valuelessness  of  the  supposedly  practical 
instruction  of  which  he  has  been  the  victim.  It  will  not  help 
him  in  the  least  to  understand  what  is  wrong  with  the  battery 
that  works  his  electric  bell  when  it  gets  out 'of  order,  the  way  in 
which  the  dye  adheres  to  his  clothes,  how  mortar  and  plaster  of 
Paris  harden  and  cement  sets,  why  his  city  dilutes  its  sewage 
with  water  to  render  it  innocuous,  why  writing  is  more  apt  to 
fade  than  printing,  how  baking  powder  and  yeast  act,  how 
photographs  and  fireworks  are  made,  why  'tin  plate'  rusts  so 
rapidly  when  it  has  started  in  one  spot  while  galvanized  iron 
does  not,  why  hard  water  uses  so  much  more  soap  than  soft, 
whence  and  how  iron,  copper,  and  other  metals  are  obtained, 
what  becomes  of  all  the  soda  and  sulphuric  acid  that  are  manu- 
factured, and  a  hundred  other  matters  which  are  of  interest  to 


chemistry  can  be  considered,  for  they  alone  can  have  anticipated  any 
appreciable  and  easily  definable  portion  of  college  work.  The  others 
may  have  anticipated,  partially  and  feebly,  portions  of  several  college 
courses,  and  will  perforce  have  to  go  without  recognition  of  this  antici- 
pation. 

A  vigorous  discussion  of  the  subject  of  instruction  in  chemistry,  with 
special  reference  to  the  place  of  qualitative  analysis,  by  Professor  Arm- 
strong in  the  presidential  address  already  mentioned  QOUR.  CHEM. 
Soc.  LXV.  361,  or  NATURE,  L.  211),  will  be  found  particularly  instruc- 
tive. He  seriously  advises  the  postponement  of  the  detailed  study 
of  qualitative  analysis  to  the  very  end  of  the  college  or  university 
course,  after  most  of  the  other  topics  which  usually  succeed  it  have  been 
taken  up.  See  also  Professor  Perkin's  vice-presidential  address  before 
the  British  Association  (Report  of  the  Association,  1900),  reprinted  in 
NATURE  LXII.  (1900),  479-480. 

12 


1/8      SOME   CONSTITUENTS   OF   THE   COURSE 

everybody,  the  basis  for  whose  explanation  might  have  been 
furnished  in  the  high  school  course  if  the  time  had  been  better 
employed. 

If  such  analysis  as  can  be  given  prematurely  furnishes  no 
more  chemistry  than  whist  (aside  from  special  efforts  more  or 

less  artificially  to    graft   chemical   knowledge   into 
Conclusions.  ,    J 

its  study),  is  no  more  or  less  capable  of  practical 

application  than  Latin,  and  positively  tends  to  confuse  what  of 
settled  order  the  previous  work  in  general  chemistry  may  have 
brought  about,  why  cherish  it  on  account  of  the  opportunities 
for  exercise  in  observation  and  reasoning  it  offers  when  a  study 
of  chemistry  in  a  broader  sense  might  give  the  same  opportuni- 
ties and  be  a  support  instead  of  a  stumbling  block  in  the  acqui- 
sition of  a  knowledge  of  the  science. 

The  choice  of  proper  subjects  of  instruction  places  a  great 
responsibility  on  the  secondary  school.  The  subjects,  to  speak 
figuratively,  should  be  fit  to  form  little  bases  of  supplies  for  use 
in  after-life,  and  the  treatment  should  make  plain  the  main 
lines  of  travel  in  each  subject.  If  the  chemical  base  is  placed 
eccentrically  with  reference  to  the  science  as  a  whole,  and  the 
roads  with  which  the  pupil  is  familiarized  turn  out  to  have  been 
by-ways  instead  of  thoroughfares,  the  knowledge  obtained  will 
have  been  useless,  if  it  does  not  even  prove  a  burden,  in  the 
subsequent  campaign  of  life. 

In  all  this  it  will  be  understood  that  we  are  speaking  of  the 
trivial  form  of  analysis,  which  is  the  only  one  it  can  assume  in 
the  hands  of  pupils  not  possessed  of  a  broad  and  thorough 
training  in  general  and  theoretical  chemistry  extending  over 
one  or  two  years.  After  such  a  training,  the  questions  of 
genuine  chemical  interest  with  which  it  is  replete  can  be  appre- 
ciated, and  its  study  becomes  in  the  highest  sense  a  study  of 
chemistry. 

c.  Exercises  in  Identification  :  —  The  satisfaction  and  apparent 
success  attending  the  use  of  qualitative  analysis  in  an  elementary 
course  show  the  need  of  some  exercises  which  shall,  if  possible, 
possess  similar  characteristics,  while  confirming  and  amplifying 


SOME   CONSTITUENTS  OF   THE   COURSE      1J9 

the  knowledge  of  the  subject  as  a  whole  rather  than  harming  it 
by  the  introduction  of  a  side  issue.  *  We  must  have  exercises 
furnishing  opportunity  for  observation  and  reason- 
ing, limited  by  suitable  restrictions;  exercises,  if  ^Analysis, 
possible,  with  an  object  in  view  that  will  awaken  the 
detective  instincts  of  the  pupil ;  and  exercises  that  will  at  the 
same  time  review  and  enlarge  the  knowledge  of  chemistry.  Can 
a  study  devoted  more  largely  to  chemical  properties  and  less 
largely  to  physical  ones  than  analysis  be  devised?  Some 
teachers  are  beginning  to  think  so.  The  attempt  to  commence 
with  the  wet  reactions  for  the  '  metals,'  however,  must  be 
abandoned. 

Suppose  we  give  a  pupil  at  some  suitable  opportunity  some 
substance  like  red  phosphorus  or  powdered  charcoal,  and  ask 
him  to  discover  what  it  is  by  employing  any  ex- 
perimental means  that  occur  to  him,  and  to  make    T]16^110^0* 

laentuication. 

a  report  showing  conclusively  that  it  is  the  sub- 
stance he  determines  it  to  be  and  no  other.  In  a  simple  case 
he  may  guess  what  the  body  is  from  its  appearance,  but  the 
furnishing  of  a  logical  proof  will  nevertheless  give  him  much 
exercise,  and  result  perhaps  in  repeated  rejections  of  the  report. 
Suppose,  next,  that  he  is  given  powdered  sodium  carbonate, 
common  salt,  calcium  nitrate,  or  sodium  hydrogen  sulphite  for 
examination  in  the  same  way,  his  task  being  to  discover  the 
acid  radical  solely.  Suppose  again  that  later  he  gets  more 
difficult  cases,  such  as  potassium  chlorate,  sodium  iodate, 
ammonium  iodide,  potassium  sulphite,  or  zinc  acetate.  Familiar 
substances  like  glycerine,  alcohol,  soap,  and  so  forth  may  even 
be  given  if  the  chemistry  of  carbon  compounds  has  received 
much  attention.  The  particular  substances  employed  must  natu- 
rally depend  upon  the  elements  and  compounds  that  have  been 
studied.  In  each  case  he  is  instructed  as  before  to  discover 
what  the  substance  is,  and  prove  its  identity  conclusively  by  ex- 
periment. It  will  probably  be  necessary  to  give  him  a  start  by 
a  little  discussion  of  the  experiments  most  likely  to  give  the 
largest  amount  of  information.  It  will  soon  be  agreed  that 


180      SOME   CONSTITUENTS   OF   THE    COURSE 

heating  a  substance  by  itself  in  a  hard  glass  test-tube,  and  again, 
in  the  case  of  inorganic  materials,  in  a  common  test-tube  with 
concentrated  sulphuric  acid,  are  likely  to  furnish  most  quickly 
a  considerable  amount  of  information. 

When  heated  alone,  few  bodies  fail  to  change  in  some  way. 
Sublimation,  melting,  boiling,  and  evidence  of  decomposition 

are  all  significant  and  will  be  noted.  If  gases  or 
Heating*  vapours  appear  to  come  off,  the  pupil  will  have  to 

reflect  on  proper  means  of  recognising  by  their 
properties  whether  they  consist  of  oxygen,  carbon  dioxide, 
water,  sulphur  dioxide,  etc.,  or  contain  more  than  one  of  these. 
Then  he  must  decide,  when  the  gas  has  been  identified,  what 
substances  could  have  furnished  it,  and,  if  possible,  taking  the 
other  facts  into  consideration,  decide  what  the  unknown  body 
was.  The  pupil  should  be  warned  to  keep  the  residue  from  this 
experiment,  since,  for  example,  any  one  of  many  kinds  of 
bodies  may  be  the  source  of  oxygen,  and  examination  of  the 
residue  to  determine  what  it  really  was  may  be  the  quickest 
way  to  limit  the  choice. 

When  the  body  is  heated  with  concentrated  sulphuric  acid, 
similar  observations  will  be  made.  Oxygen,  carbon  dioxide, 
Action  of  sulphur  dioxide,  etc.,  may  be  recognised  by  specific 
Sulphuric  properties.  Dense  clouds  of  fumes  will  usually 

indicate  the  halogen  hydrides  or  nitric  acid. 
Coloured  solids  like  iodine  and  free  sulphur  may  be  seen.  A 
few  salts,  such  as  phosphates  and  sulphates,  will  give  no  visible 
action.  Of  course  everything  noticed  and  the  inferences  drawn 
will  be  recorded.  If  these  two  experiments  do  not  lead  to  a 
definite  conclusion,  the  examination  of  the  residue  of  the  former 
will  usually  assist  very  materially.  For  example,  it  may  itself 
be  treated  with  concentrated  sulphuric  acid.1 

Naturally  the  reports  first  presented  will  almost  always  be 


1  An  account  of  the  inferences  which  maybe  drawn  from  the  results  of 
these  and  similar  dry  way  tests  will  be  found  inW.  A.  Noyes'  Qualitative 
Analysis  (1898),  54-56,  in  Valentin's  Qualitative  Analysis  (1898),  213  and 
231,  and  other  similar  works. 


SOME   CONSTITUENTS   OF  THE   COURSE      iSl 

inconclusive.  If  a  gas  is  given  off  which  burns,  it  will  be  desig- 
nated hydrogen.  When  the  pupil  is  asked  how  he  knew  it 
was  not  hydrogen  sulphide,  he  will  probably  not 
be  able  to  recall  any  reason.  On  returning  with 
a  definite  report,  say,  to  the  effect  that  it  had  no 
odour,  he  will  then  be  confronted  with  the  suggestion  that  it 
might  have  been  carbon  monoxide,  and  so  a  fresh  investigation 
will  be  started.  Or  if  he  reports  oxygen,  and  has  not  excluded 
the  possibility  of  its  being  nitrous  oxide,  the  fact  should  be 
pointed  out.  If  he  reports  potassium  chlorate,  he  is  asked  how 
he  knew  it  was  not  the  perchlorate  or  hypochlorite.  Each  of 
these  questions  at  once  appeals  to  him,  his  pride  is  stimulated, 
and  he  rushes  off  to  renewed  experiment  and  to  investigation  of 
his  laboratory  notes,  or,  if  these  fail,  of  the  books  provided  for 
reference.  Of  course  the  success  of  the  system  depends  upon 
the  neighbours  in  the  laboratory  receiving  different  substances, 
and  upon  the  alertness  of  the  teacher  in  suggesting  means  of 
making  the  report  more  logical  and  conclusive.  This  sort  of 
work  invariably  arouses  the  interest  of  the  pupils  to  the  highest 
pitch,  and  a  single  exercise  in  identification  will  teach  them 
more  about  chemistry  than  they  have  learned  in  months  of 
ordinary  instruction,  and  they  will  be  the  first  to  draw  attention 
to  this  fact.  Of  course  it  would  have  had  neither  interest,  nor 
object,  nor  possibility  of  success  without  the  previous  drudgery. 
This  work  is  not  capable  of  being  arranged  in  a  system  so 
simple  that  its  employment  becomes  mechanical.  The  range 
of  observation  is  wider  than  in  wet  way  tests,  and  Benefits  of 
chemical  knowledge  is  demanded  continually.  That  this  Work, 
it  furnishes  exercise  in  observation  and  reasoning,  however, 
does  not  require  to  be  pointed  out.  That  it  takes  advantage  of 
the  various  qualities  of  human  nature  which  hold  the  attention 
and  even  awaken  enthusiasm,  is  one  of  its  most  conspicuous 
characteristics.  That  it  must  furnish  a  review  of  most  of  the 
chemical  properties  and  modes  of  preparation  of  the  non- 
metals  and  their  compounds,  and  this  in  the  most  practical 
way,  is  evident.  Above  all,  after  one  or  two  attempts  at  in- 


1 82      SOME   CONSTITUENTS  OF  THE   COURSE 

vestigation  of  this  kind,  the  pupil  experiences  a  feeling  of  self- 
reliance  and  of  ability  really  to  do  something  with  his  chem- 
istry, which  is  necessarily  stronger  and  more  gratifying  than  it 
would  be  in  the  use  of  a  cut  and  dried  system  that  left  little 
room  for  variety  of  procedure  and  independent  thought,  like 
the  common  scheme  of  wet  way  analysis.  It  may  be  added 
that  a  pupil  with  but  little  training  will  be  as  successful  in  this 
work,  provided,  of  course,  no  cases  of  exceptional  difficulty  are 
presented  to  him,  as  another  who  has  been  prematurely  trained 
in  formal  analysis,  and  he  will  usually  reach  his  results  more 
quickly,  and  what  is  much  better,  will  know  precisely  how  he 
reached  them.  I  have  heard  of  students  of  analysis  spending 
two  days  in  looking  for  the  acid  radical  in  an  alloy.  Students 
of  analysis  are  in  danger  of  being  slaves  to  the  system  and  of 
using  the  whole  of  it  every  time.  They  are  often  like  the 
guides  to  show  places  in  Europe,  who  get  on  nicely  if  they 
are  allowed  to  deliver  their  accustomed  harangue  without  any 
appeal  to  their  intelligence,  but  who  are  paralyzed  if  they 
allow  themselves  to  be  interrupted  to  answer  a  common-sense 
question. 

Work  of  the  kind  we  have  described  takes  a  good  deal  of 
time,  but  its  extreme  instructiveness  far  more  than  makes  up 
for  this.  If  any  time  remains  at  the  end  of  the  year,  there  is 
no  reason  why  the  process  of  identification  should  not  be 
extended  to  the  metallic  part  of  the  compounds  given  for 
examination. 

V.     The  General  Content. 

It  would  be  needless  to  attempt  to  suggest  what  other  mat- 
ters should  make  up  the  course  in  chemistry  aside  from  the 
Principles  of  topics  we  have  discussed.  Facts,  and  many  of 
Selection.  them,  are  needed  for  the  foundation  of  general- 
ization and  theory,  and  for  the  illustration  of  the  chemistry  of 
the  important  elements  and  compounds.  The  selection  of  facts 
for  this  purpose  must  differ  in  different  institutions  according  to 
the  capacities  and  needs  of  the  pupils,  the  taste  of  the  teacher, 


.SOME   CONSTITUENTS  OF   THE   COURSE      183 

and  a  hundred  other  circumstances.  As  a  general  suggestion, 
however,  a  statement  of  the  Committee  on  College  Entrance 
Requirements  may  be  recalled,  as  it  is  sufficiently  important  in 
this  connection  to  justify  quotation":  "  Facts  incapable  of  cor- 
relation should  be  avoided  as  far  as  possible, "uand  again  :  "The 
facts  should  be  given  as  examples  from  various  classes,  and  not 
as  isolated  things.  Thus  to  speak  of  a  '  standard  method  of 
preparing  hydrogen,'  whereby  the  action  of  zinc  on  hydro- 
chloric acid  is  meant,  shows  narrow  and  infertile  teaching.  It 
should  be  shown  that  all  acids  are  acted  upon  by  a  certain  class 
of  metals  to  produce  hydrogen.  Examples  of  both  classes  of 
metals  should  be  given  and  the  general  principles  derived.  The 
reason  for  using  zinc  and  hydrochloric  acid  in  the  laboratory 
can  then  be  stated." 

The  outline  of  work  for  a  secondary  school  course  in  chem- 
istry, which  is  most  fully  worked  out  in  detail,  is  that  prepared 
by  the  Committee  of  Nine,  to  which  repeated  refer-  outlines  Sug- 
ence  has  been  made  already.  They  show  what,  in  fjjf^jj^ 
their  estimation,  is  a  proper  content  and  order  for  Bodies. 
presenting  the  subject,  and  by  useful  comments  point  out  the 
relations  of  the  theoretical  topics  to  one  another.  They  indi- 
cate also  the  way  in  which  experimental  illustrations  should  be 
distributed  between  the  laboratory  and  classroom.  It  seems 
to  me  to  be  the  best  outline  of  what  the  American  high  school 
can  and  should  be  expected  to  do.  Excellent  scientific  judg- 
ment and  practical  knowledge  of  the  condition  of  the  schools 
are  shown  at  every  point  in  the  report. 

The  syllabus  of  the  Examination  Board  of  the  Association  of 
Colleges  of  the  Middle  States  and  Maryland  is  founded  upon 
the  report  of  the  Committee  on  College  Entrance  Require- 
ments. It  is  much  less  detailed  than  the  above,  but  the  scope 
of  work  which  it  indicates  is  practically  the  same.  A  useful  list 
of  laboratory  experiments,  which  is  well  selected  and  represen- 
tative, has  been  appended  by  the  Examination  Board. 

The  syllabus  issued  by  the  Regents  of  the  University  of  the 
State  of  New  York  cannot  be  commended  without  reserve. 


1 84      SOME    CONSTITUENTS   OF   THE   COURSE 

The  laws  of  chemistry  seem  to  receive  too  little  consideration. 
The  only  one  of  the  quantitative  laws  mentioned  is  that  of 
definite  proportions,  yet  they  presently  ask  for  a  knowledge 
of  the  "theory  of  valency"  which  cannot  be  obtained  without 
the  study  of  Avogadro's  hypothesis,  and  all  that  it  implies. 
They  include  also  the  atomic  theory,  although  there  is  noth- 
ing which  calls  for  the  use  of  this  theory  so  long  as  the  sub- 
jects of  multiple  proportions  and  of  equivalent  proportions  are 
omitted.  The  laboratory  work  which  is  suggested  is  too  brief. 
It  contains  also  nothing  on  the  chemistry  of  the  metals  and 
their  compounds,  and  none  of  the  fundamental  principles  of 
the  subject  are  illustrated  in  it  with  the  exception,  strange  to 
say,  of  the  law  of  mass  action.  Even  this  is  referred  to,  how- 
ever, in  so  questionable  a  way  (see  Experiments  15  and  24), 
that  it  might  better  have  been  omitted.  Of  course  every- 
thing depends  on  the  use  which  a  teacher  may  make  of  any 
outline,  but  this  one  certainly  does  little  to  discourage  dis- 
jointed work  and  the  neglect  of  the  principles  for  accumulation 
of  facts. 

The  detailed  statement  of  the  admission  requirements  to 
Harvard  College  contains  much  theory  in  proportion  to  the 
number  of  facts.  It  is  exceedingly  well  put  together  and 
highly  instructive.  Probably  the  explanation  of  the  emphasis 
upon  theory  may  be  found  at  least  as  much  in  the  nature  of 
the  instruction  in  the  college  itself  as  in  consideration  for  the 
needs  of  the  pupils  in  the  secondary  school  who  may  never  go 
to  college  at  all. 

VI.     The  Selection  of  the  Text-Book  and  Laboratory  Manual. 

This  subject  is  closely  connected  with  the  last,  and  the  choice 
of  books  must  depend  on  so  many  circumstances  that  definite 
recommendations  cannot  be  made.  It  may  be  useful  here, 
however,  to  recall  the  points  bearing  on  this  question  which 
have  been  discussed  in  the  present  volume,  and  to  summarize 
them  in  their  application  to  the  choice  of  books.  Naturally 


SOME   CONSTITUENTS  OF  THE   COURSE      185 

these  statements  are  intended  to  apply  to  the  average  case 
only,  and  in  common  with  all  statements  on  difficult  questions 
like  this,  must  be  subject  to  numerous  exceptions. 

In  general,  a  book  which  gives  a  plain  account  of  the  sub- 
ject without  t$o  much  pedagogical  pretence  will  be  best  suited 
to  the  use  of  the  teacher  who  knows  his  subject.  ^e  Text- 
It  is  unnecessary  to  say  that  it  should  be  accurate,  Book- 
and  not  only  accurate  in  its  statements,  but  it  should  present  a 
view  of  the  science  as  close  to  that  occupied  by  the  scientific 
chemist  as  is  consistent  with  its  elementary  character.  It 
should  deal  almost  exclusively,  so  far  as  facts  go,  with  the  com- 
mon elements,  and  a  not  too  numerous  selection  of  their 
prominent  compounds.  Works  of  reference  can  be  used  for 
amplifying  the  information  which  it  gives. 

The  spirit  of  the  book  should  be  inductive  ;  the  laws  should 
be  carefully  explained  as  summaries  of  facts  which  have  been 
given  and  in  close  relation  to  them.  Theories  should  likewise 
be  closely  related  to  facts  and  should  follow  them.  The  gen- 
eral treatment  should  be  connected,  logical,  and  lucid,  and 
should  make  the  unity,  rather  than  the  diversity,  of  the  sub- 
ject apparent. 

The  book  should  treat  of  general  chemistry  in  a  sound 
fashion  and  as  a  pure  science.  It  should  not,  for  example, 
be  arranged  as  an  introduction  to  analysis. 

Formulae  should  be  kept  in  their  proper  places,  and  shown  to 
be  receptacles  for  the  results  of  the  study  of  each  action.  They 
should  not  in  any  sense  appear  to  be  themselves  the  end  of 
study  in  chemistry.  The  way  in  which  the  facts  are  translated 
into  formulae,  as  a  sort  of  language  or  shorthand  for  expressing 
them,  should  be  explained  clearly,  that  no  misunderstanding 
may  arise. 

The  outline  of  laboratory  work  or  laboratory  manual  should 
fulfil  the  requirements  which  we  have  discussed  in  Chapter  IV. 
It  should  plainly  exhibit  coherence  in  the  study  of    The  Labora. 
each  topic,  or  at  least  should  be  capable  of  yielding  tory  Manual, 
results  in  which  this  coherence  may  be  brought  out.     The  out- 


1 86      SOME   CONSTITUENTS  OF  THE   COURSE 

line  of  each  experiment  should  be  a  thoroughly  sufficient  guide 
to  the  pupil,  without  being  overburdened  with  detail,  and  with- 
out foretelling  the  result ;  the  manner  of  presentation  should 
encourage  and  assist  thought ;  the  selection  should  be  judicious  ; 
and,  above  all,  the  principles  of  the  science  should  be  illustrated, 
as  well  as  the  facts. 


CHAPTER   VII 

THE   LABORATORY,  EQUIPMENT   AND   ILLUSTRATIVE 
MATERIAL 

REFERENCES. 

Whitney,  E.  R.  Equipment  of  Secondary  School  Laboratory.  High 
School  Bulletin  No.  7.  Albany,  N.  Y.,  The  University  of  the  State  of 
New  York.  Pp.  665-675.  The  whole  of  the  paper  is  valuable  and  has 
furnished  many  suggestions  for  this  chapter. 

Arey,  A.  L.  Management  of  Laboratory  Classes  in  Chemistry.  Ibid. 
Pp.  676-678. 

Gibson,  James  H.  Selection  and  Care  of  Apparatus.  High  School 
Bulletin  No.  i.  Albany,  N.  Y.,  The  University  of  the  State  of  New 
York.  Pp.  362-366. 

Catalogues  of  dealers  in  laboratory  supplies. 

THE  attempt  should  not  be  made  to  give  instruction  in  chem- 
istry in  any  school  which  is  not  provided  with  a  laboratory 
fairly  well  equipped  for  the  purpose.  It  should  certainly  never 
be  taught  without  laboratory  work,  and  a  poorly  furnished  lab- 
oratory means  prodigious  loss  of  time  both  to  the  pupil  and  to 
the  teacher,  and  many  difficulties  in  discipline  and  class  manage- 
ment. If,  however,  the  authorities  insist  upon  the  teaching  of 
the  subject  when  no  laboratory  exists,  a  strenuous  effort  should 
be  made  to  provide  some  tentative  arrangement  of  an  inexpen- 
sive kind  in  order  that  this  indispensable  feature  may  not  be 
entirely  omitted. 

I.     Accommodations  required. 

First  in  order  comes  the  laboratory  itself,  which  should  be 
large  enough  to  hold  the  necessary  furniture  and  provide  plenty 
of  space  for  the  moving  about  which  the  work  entails.1  Close 

1  For  full  discussion  of  the  arrangement  of  benches  with  reference  to 
space  and  light,  see  Minot,  SCIENCE  [N.  S.J,  XIV.  (1900),  412. 


1 88  THE  LABORATORY 

to  this  should  be  the  store-room,  which  should  not  be  made  too 
small,  if  perfect  order  is  to  be  kept  amongst  the  material  it 
contains.  A  large  well  lighted  closet  may  per- 
haps serve  this  purpose  in  a  small  school.  The 
classroom  will  probably  be  shared  by  other  classes  in  physics 
and  perhaps  biology.  A  private  room  for  the  teacher  is  indis- 
pensable. A  balance  room,  with  shelves  resting  on  brackets 
attached  to  the  walls,  is  extremely  desirable,  as  the  distraction  of 
attempting  to  weigh  in  a  crowded  laboratory  interferes  with 
care  and  exactness.  The  fumes  of  the  laboratory  also  damage 
the  instruments.  A  dark  room  for  photographic  work  is  a 
convenience. 

It  is  needless  to  say  that  all  the  rooms  should  be  well  lighted, 
provided  with  sound-proof  floors  and  partitions,  and  perfectly 
ventilated.  Artificial  ventilation  by  fans  is  the  best,  if  it  can  be 
had.  Aside  from  the  ordinary  heating  arrangements,  live  steam 
for  the  production  of  distilled  water  and  for  the  steam  baths 
will  be  required.  The  rooms  should  be  furnished  with  gas 
connections  for  lighting,  and  the  tables  and  hoods  with  light- 
ing or  fuel  gas  for  experimental  work.  Water  should  be  pro- 
vided on  "all  the  tables  and  in  the  hoods,  and  electrical  connec- 
tions are  desirable. 

One  of  the  prime  necessities  is  a  willing  and  intelligent  jani- 
tor, and  the  maintenance  of  perfect  cleanliness  through  his 
efforts.  Mr.  E.  R.  Whitney  puts  this  exceedingly 
well  when  he  says :  "  The  activities  of  the  pupil 
are  largely  influenced  by  his  surroundings.  There  is  an 
intimacy  between  environment  and  conduct,  and  character  is 
the  outgrowth  of  conduct.  A  dirty,  poorly  lighted,  inconven- 
ient room,  though  designated  as  a  laboratory,  containing  broken 
apparatus  and  dilapidated  furniture,  breeds  slovenliness,  disorder, 
and  degradation.  Bright,  cheerful  rooms,  kept  neat  and  tidy, 
supplied  with  good  apparatus  and  inspiring  pictures,  will  be  a 
powerful  aid  toward  the  formation  of  high  ideals  and  the 
arousing  of  noble  aspirations.'* 


THE  LABORATORY  189 

II.     Laboratory  Furniture. 

a.  The  Desks  :  —  These  should  be  three  feet  in  height  with 
tops  two  feet  wide,  and  the  working  places  should  be  three  feet 
six  inches  long.  The  total  length  of  a  desk  will  de- 
pend on  the  size  of  the  room,  but  should  in  no  case 
contain  more  than  four  or  five  places.  The  desks  may  be 
placed  back  to  back  in  pairs.  The  tops  may  be  made  of  some 
hard  wood.  Paraffin  should  be  ironed  into  them.  This  fur- 
nishes almost  perfect  protection  from  damage.  Plate  glass 
(three-eighths  of  an  inch  thick,  resting  on  rubber),  slate,  and 
tiling,  are  frequently  employed.  Perhaps  the  best  material  is  a 
form  of  soapstone,  made  by  the  Alberene  Stone  Co.,  Chicago. 
It  is  indestructible.  Glass  apparatus  is  not  more  liable  to  break- 
age where  it  is  used  than  when  wood  is  employed.  The  tops  of 
the  tables  should  be  clear,  the  shelves  and  connections  being 
carried  sufficiently  high  above  them  to  make  cleaning  easy. 

As  more  than  one  section  may  occupy  the  room,  the  space 
under  each  place  should  be  divided  vertically.  For  two  sec- 
tions, two  cupboards  with  one  or  two  drawers  above  each  will 
provide  accommodation  for  the  apparatus.  If  there  are  more 
sections  than  two,  or  if  economy  in  equipment  is  desired,  one 
cupboard  containing  the  less  breakable  materials  may  be  used 
by  all  the  occupants  in  common,  and  from  four  to  six  drawers, 
occupying  the  other  side,  may  be  assigned  to  different  indi- 
viduals, according  to  the  number  of  sections.  Combination  or 
ordinary  locks  or  padlocks,  to  which  the  teacher  carries  a 
master  key,  will  be  necessary  on  all  cupboards  and  drawers. 

A  shelf  running  down  the  centre  of  each  double  desk  will 
hold  a  few  reagents.     Glass  shelves  with  iron  supports  are  ad- 
mirable.    They  obscure  the  light  less  than  wood,  and  are  not 
harmed  by  acids.     Six  bottles  containing  the  three 
common  acids  in  diluted  and  concentrated  form, 
and   three   containing   solutions    of    sodium    and   ammonium 
hydroxides    and    sodium    carbonate    will    usually    suffice    for 
general  chemistry.     The  stoppers  of  the  last  three  bottles  should 


190  THE  LABORATORY 

be  covered  with  paraffin,  or  rubber  stoppers  should  be  substi- 
tuted for  them.  Ordinary  glass  stoppers  continually  become 
fast  in  the  mouths  of  the  bottles,  which  are  broken  in  large 
numbers  in  the  attempt  to  open  them. 

The  fuel  gas  may  be  led  in  a  horizontal  pipe  under  the  shelf,  or 
vertical  pipes  may  rise  to  the  surface  of  the  table  and  terminate 
Gas  and  *n  a  piece  carrying  four  narrow  exits  for  rubber  tube 

water.  connections.  The  sinks  of  alberene  may  either  be 

placed  in  the  corner  between  two  adjacent  and  two  opposite 
places,  thus  serving  for  all  four  pupils,  or  at  the  ends  of  the 
desks.  In  the  latter  case,  an  open  trough,  lined  with  lead  or 
alberene,  running  down  the  centre  under  the  shelf,  is  useful. 
Narrow  exits  for  water  placed  over  the  trough  furnish  means 
for  attaching  condensers,  and  should  be  threaded  for  carrying 
water  pumps.  In  any  case  the  water  faucet  over  the  sink 
should  be  placed  somewhat  high,  to  prevent  breakage  of  appara- 
tus. It  is  exceedingly  important  that  the  exit  of  each  sink 
should  be  provided  with  a  cap  perforated  at  the  top,  in  order 
that  at  least  an  inch  and  a  half  of  water  may  always  remain 
standing  in  the  sink.  Thus  strong  acids  are  diluted  before 
entering  the  lead  pipe,  and  solids  have  an  opportunity  to  settle. 
With  this  arrangement,  ordinary  lead  and  iron  pipes  will  serve 
for  the  drainage  of  the  laboratory,  and  will  last  for  years. 
Without  these  caps  the  pipes  are  quickly  eaten  away,  and  be- 
come plugged  up  as  well. 

If  they  can  be  accommodated,  recesses  for  the  stools  and 
the  waste  jars,1  of  which  there  should  be  at  least  one  to  every 
Other  four  working  places,  may  be  provided  under  the 

Fittings.  desk.  Sometimes  economy  in  equipment  may  be 
effected  with  little  loss  in  convenience  by  the  use  of  projecting 
strips  of  wood  perforated  with  two  or  three  holes  to  serve  as 
filter  stands,  and  by  fixing  iron  rods  in  the  table  to  take  the 


1  Buckets,  "  Buggy  pails,"  made  by  the  Indurated  Fiber  Co.,  Water 
Street,  Chicago,  are  cheaper  than  stone-ware  jars,  look  better,  and  last 
as  long.  The  same  firm  makes  "  Keelers,"  circular,  flat-bottomed,  shal- 
low vessels,  which  make  excellent  pneumatic  troughs. 


THE  LABORATORY  19 1 

place  of  ring  stands.  Rods  eighteen  inches  long  and  three- 
eighths  of  an  inch  in  diameter  will  cost  little,  and  will  serve  the 
purpose  very  well.  The  invention  of  some  form  of  accommo- 
dation for  the  laboratory  directions  and  note-books,  which  would 
not  interfere  with  the  use  of  the  drawer  or  cupboard,  or  with 
the  work  being  performed,  would  confer  a  boon  upon  the  stu- 
dent in  chemistry. 

When  gas  can  be  obtained,  the  Bunsen  burner  will  naturally 
be  used  for  heating.  In  the  absence  of  this  great  convenience, 
a  small  apparatus  for  making  gasoline  gas  is  a  substi- 
tute, which,  however,  is  only  moderately  satisfactory. 
A  convenient  acetylene  generator,  and  a  special  form  of  Bunsen 
burner  for  use  with  it,  are  made  by  J.  B.  Colt  &  Co.,  Boston. 
The  alcohol  lamp  is  feeble  and  expensive ;  it  may  be  supple- 
mented by  the  use  of  a  gasoline  blast 1  when  higher  tempera- 
tures are  required.  For  many  purposes,  ordinary  small  kero- 
sene stoves  (see  figure  in  Cooke,  ibid.,  193)  will  be  found 
useful  in  the  absence  of  gas. 

b.  The  Hoods :  —  For  the  performance  of  experiments  in- 
volving the  evolution  of  noxious  vapours,  well-ventilated  hoods 
should  be  provided.  One  section  of  a  hood  will 
be  required  for  every  four  or  five  workers.  In 
some  cases,  the  hoods  are  placed  on  the  desks,  in  others,  along 
the  side  of  the  room.  Flues,  in  the  lower  openings  of  which 
gas  jets  can  be  lighted,  will  serve  the  purpose  in  the  absence  of 
better  means  of  ventilation.  If  connection  with  a  fan  is  pos- 
sible, however,  it  should  be  made.  The  floors  of  the  hoods 
should  be  clear  in  order  that  they  may  be  easily  cleaned.  Gas 
and  water  connections  are  best  placed  below  the  floor  of  the  hood, 
close  to  the  front,  and  the  rubber  tubing  for  attachments  is  passed 
through  a  small  hole  opposite  each  stop-cock.  One  or  two 
pipes  for  waste  water  should  rise  at  the  back  of  the  hood  and 
open  flush  with  the  surface.  At  least  one  sink  should  be  ac- 


1  Convenient  forms  of  this,  which  work  satisfactorily,  are  listed  and 
figured  by  the  Chicago  Laboratory  Supply  and  Scale  Company,  39  W. 
Randolph  St. 


192  THE  LABORATORY 

commodated  in  a  hood  in  order  that  ill-smelling  liquids  may  be 
disposed  of  without  discomfort  to  the  occupants  of  the  room. 
It  should  be  fitted  in  the  same  way  as  the  other  sinks. 

c.  The  Side-Shelves :  —  Conveniently  accessible  shelves 
should  be  placed  against  the  wall  for  the  accommodation  of 
chemicals.  The  solids  used  in  considerable  quan- 
tities may  be  placed  in  large  stoppered  bottles 
(say  one  litre).  For  most  of  the  chemicals  smaller  bottles 
(say  200  c.c.)  will  be  sufficient.  The  liquids  may  be  accom- 
modated in  half-litre  bottles.  The  reagents  should  be  carefully 
labelled  and  arranged  in  alphabetical  order,  according  to  some 
definite  system,  upon  the  shelves.  The  bottles  and  their  places 
on  the  shelves  should  be  numbered  'consecutively  with  asphalt 
paint.  The  labels  should  be  painted  with  melted  paraffin  to 
prevent  defacement.  It  will  be  found  that  the  books  of 
printed  labels  usually  employ  an  unsystematic  and  often  incor- 
rect nomenclature,  while  the  formulae  they  give  are  frequently 
erroneous. 

The  solutions  should  always  be  made  of  a  fixed  concentration, 
which  is  marked  plainly  on  the  label.  It  is  better  to  furnish 
ready-made  solutions  than  to  direct  the  student  to  make  them, 
except  in  the  case  of  special  exercises,  as  the  latter  method 
gives  uncertain  results,  and  always  entails  great  waste  of  mate- 
rials. It  should  be  noted  that  more  than  one  solution  of  the 
same  substance,  differing  in  concentration,  is  sometimes  re- 
quired, and  that  in  general  the  best  concentrations  are  not  the 
same  as  those  used  in  qualitative  analysis. 

A  list  of  the  chemicals  required  can  hardly  be  given,  as  it 
must  vary  somewhat  with  the  work.  Many  text-books 1  furnish 
a  list  of  materials  needed.  As  regards  special  substances,  it 
should  be  noted  that  red  phosphorus  can  almost  always  be 


1  For  example,  Williams,  Elements,  398 ;  Perkin  and  Lean,  327 ;  Newell, 
381  ;  Young,  Suggestions  to  Teachers,  42  ;  Cooley,  Laboratory  Studies,  139; 
Shepard,  Elements  of  Chemistry,  343  ;  Nicholson  and  Avery,  Laboratory 
Manual,  125.  Torrey,  47  5,  and  Arey,  Elementary  Chemistry,  xi,  give  lists 
of  apparatus  only ;  the  others,  apparatus  and  chemicals  as  well. 


THE  LABORATORY  193 

employed  as  well  as  the  yellow  variety,  and  is  much  safer  to 
handle.  A  solution  of  ferrous  sulphate  had  better  not  be  fur- 
nished, as  it  rapidly  oxidizes.  In  place  of  solid  ferrous  sulphate, 
ammonium  ferrous  sulphate  is  preferable,  as  it  keeps  much  bet- 
ter, and  is  not,  therefore,  so  liable  to  give  misleading  results.  A 
solution  of  this  double  salt  containing  a  little  sulphuric  acid  will 
keep  for  months  without  much  oxidation  (Noyes).  A  solu- 
tion of  tartaric  acid  should  be  made  immediately  before  use, 
as  moulds  grow  in  it  when  the  attempt  is  made  to  keep  it  on 
the  shelf. 

d.    Other   Laboratory   Furniture:  —  A    cabinet   containing 
drawers   divided  into  compartments  and   filled  with  corks  of 
various   sizes    is  necessary.      In   the   same    place 
accommodation   may    be   found   for   pliers,   files,  neous  Fur- 
copper   wire  (thick   and   thin,  say   Nos.    16   and  mture> 
22),  and  cork  borers,  all  for  general  use. 

A  broad  shelf  attached  to  the  wall,  or  a  small  table,  furnished 
with  gas  connections  and  covered  with  a  sheet  of  asbestos  board, 
will  serve  for  the  blast  lamp. 

An  ordinary  table  for  readers  and  a  book-shelf  for  the  most 
necessary  works  of  reference  should  not  be  omitted.  The  books 
will  be  used  ten  times  more,  if  placed  in  the  laboratory,  than  if 
they  are  to  be  found  in  a  separate  room  only.  The  carrying  of 
the  books  to  the  working  places,  however,  should  be  forbidden, 
as  otherwise  they  are  sure  to  be  damaged. 

A  blackboard,  and,  if  the  method  of  filing  note-books  in  the 
laboratory  is  adopted,  a  shelf  near  the  door,  complete  the 
furniture  of  the  room. 

III.     Laboratory  Equipment. 

For  the  general  service  of  the  laboratory,  an  apparatus  for  the 
preparation  of  distilled  water  will  be  needed.     If  the  steam  is 
sufficiently  clean,  any  tinner  can  make  an  appara 
tus  for  its  condensation  at  small  cost.     The  worm 
should  be  made  of  tin  pipe,  as  this  metal  is  least  affected  by 


194  THE  LABORATORY 

water  and  air.  If  steam  is  not  available,  the  necessary  boiler, 
preferably  of  copper,  can  be  made  to  the  order  of  the  teacher. 
Many  different  varieties  are  on  sale.  A  very  compact  one  is 
made  by  Richards  &  Co.,  New  York.  It  should  be  placed  near 
a  sink  with  running  water,  in  order  that  the  supply  of  cold  water 
for  condensing  the  steam  may  be  readily  attached. 

As  each  pupil  is  provided  with  but  one  burner,  it  is  a  great 
convenience  to  have  a  large  steam  bath  for  general  use.     In 

quantitative  experiments  some  kind  of  steam  bath 
Steam  Baths.    .  •     «     •    j-  vi          i       ^  •    i 

is  practically  indispensable,  and  a  large  one  is  less 

expensive  than  many  separate  small  ones.  After  trial  of  many 
forms,  I  have  found  that  the  following  arrangement  is  perfectly 
effective,  runs  practically  without  any  attention,  and  can  never 
dry  up,  and  so  suffer  damage  from  overheating.  It  consists  of  a 
rectangular  box  of  sheet  copper,  four  inches  in  depth,  and  of 
size  according  to  the  needs  of  the  class  and  the  space  in  which 
it  is  placed.  The  cover  is  carried  upon  feet  projecting  to  the 
bottom  of  the  box,  and  reaches  to  within  a  fraction  of  an  inch  of 
the  top.  It  is  perforated  with  openings  one  and  three-fourths 
inches  in  diameter  for  the  accommodation  of  the  evaporating 
dishes.  An  ordinary  iron  pipe,  one-half  inch  in  internal  diam- 
eter, closed  at  one  end  and  perforated  at  intervals  of  an  inch 
and  one-half,  rests  diagonally  on  the  bottom.  At  the  open  end 
it  rises  vertically  and  projects  through  a  hole  in  one  corner  of 
the  lid.  At  this  point  it  is  connected  with  the  supply  of  steam. 
The  outflow  pipe  for  the  accumulating  water  is  attached  so  that 
its  lower  side  is  about  an  inch  below  the  lid.  This  bath  should 
be  situated  in  one  of  the  hoods,  with  the  overflow  discharging 
into  one  of  the  pipes  provided  for  waste  wate'r.  The  whole 
apparatus  can  quickly  be  taken  apart  if  cleaning  is  required. 
The  steam  connections  should  include  a  suitable  valve  to  pre- 
vent the  return  of  the  water  into  the  steam-pipe,  if  the  supply 
of  steam  in  the  building  should  be  shut  off.  Large  sand  baths 
are  sometimes  used  in  laboratories,  but  they  become  filthy  from 
the  spilling  of  material  into  them,  and  are  difficult  to  clean. 
Luxuries,  like  electrically  heated  plates,  are  usually  beyond  the 


THE  LABORATORY  1 95 

reach  of  the  school  laboratory.  They  are  very  convenient, 
however. 

A  pair  of  scales  and  weights  for  rough  weighings  will  be 
needed.  The  platform  variety,  with  a  sliding  weight  which 

takes  the  place  of  the  ordinary  weights  up  to  five 

/         r  •      XT        11          \     •  i_          Scales,  etc. 

grams  (see   figure    in    Newell,    12),  is    the    best. 

The  small  weights  up  to  five  grams  will  infallibly  be  lost,  prob- 
ably during  the  very  first  exercise,  if  the  common  form  of 
scales  is  used. 

Foot  bellows  and  a  blast  lamp,  a  barometer  and  a  thermom- 
eter, are  among  the  other  necessary  articles.  In  experiments 
which  require  large  quantities  of  certain  gases,  much  time  is 
saved  by  the  use  of  generators,  or  by  furnishing  the  gases  in 
the  liquid  or  compressed  form.  Kipp's  generators l  are  the 
most  commonly  used.  Oxygen  compressed  in  cylinders,  and 
liquid  sulphur  dioxide  in  glass  bottles  resembling  siphons  in 
appearance  are  also  obtainable. 

The  balances  have  already  been  discussed  (p.  116).  The 
chief  source  of  trouble  is  the  tendency  which  the  pupils  have  to 
lose  the  small  weights.  If  a  sufficient  number  of  sets  of  weights 
can  be  afforded,  each  pupil  should  receive  one,  and  thus  be 
held  individually  responsible  for  its  return  in  complete  form. 
If  a  more  delicate  balance  is  required  for  any  special  purpose, 
the  Sartorius  balance,  No.  3  (the  less  highly  finished  pattern), 
will  be  found  sufficiently  delicate  for  all  quantitative  work. 

IV.     Apparatus  and  Chemicals  and  the  Store-Room. 
While  the  labour  of  managing  this  necessary  accompaniment 
of  the  teaching  of  chemistry  is  exceedingly  irksome,  there  is 
nothing  which  contributes  to  making  the  work  suc- 
cessful more   than    a  businesslike   organization   of  Distribution 
the  way  in  which  the  materials  are  handled.     Each   of  Apparatus- 
pupil  should  be  furnished  with  a  set  of  the  apparatus  of  which 

1  For  an  inexpensive  generator,  modified  from  a  design  of  Ostwald's, 
see  AM.  CHEM.  JOUR.,  XXI.  (1899),  70.  Another  form  is  described 
in  SCHOOL  SCIENCE,  I.  88 ;  a  chlorine  generator  is  described  by  Cornish, 
loc.  cit.,  21.  See  also  Peter's  Modern  Chemistry,  373. 


196  THE  LABORATORY 

he  stands  most  commonly  in  need.  Apparatus  which  he  re- 
quires but  seldom  may  be  drawn  from  the  store-room,  and  its 
prompt  return  should  be  exacted.  In  order  that  the  pupil 
may  feel  his  complete  responsibility  for  the  preservation  of  the 
materials,  and  may  use  them  with  care  and  lock  them  away 
systematically  after  work,  it  is  a  good  plan  to  furnish  him  at  the 
beginning  with  a  printed  or  mimeographed  list  of  the  mate- 
rials he  has  received.  This  may  also  show  the  price  at.  which, 
when  the  apparatus  is  checked  up,  all  articles  missing,  whether 
through  having  been  broken,  lent,  or  left  lying  about,  will  be 
charged.  After  comparison  of  the  list  with  the  apparatus,  the 
former  may  be  signed  by  the  pupil  and  returned  to  the  store- 
room, where  it  is  kept  as  a  receipt.  At  the  end  of  the  year,  if 
everything  is  returned  undamaged,  no  charge  will  be  made.1 
There  are,  however,  some  pieces  of  apparatus,  such  as  towels, 
files,  and  wire  gauze  which,  if  furnished  at  all,  necessarily  can- 
not be  issued  again  after  they  have  once  been  used.  The 
Bunsen  burner  and  clamp,  also,  usually  become  corroded  dur- 
ing a  year's  use,  and,  if  given  out  again  uncleaned,  any  damage 
which  may  occur  to  them  will  be  attributed  to  the  previous 
user.  It  is  a  good  plan,  therefore,  to  have  these  articles  com- 
pletely renovated  during  the  summer  vacation  in  order  that 
nothing  but  fresh  apparatus  may  be  given  out.2 

On  the  opposite  page  is  shown,  on  a  reduced  scale,  a  sheet 
like  that  whose  use  has  been  suggested.  The  lower  portion 
Lists  and  contains  materials  which  are  unreturnable,  and  are 
Blanks.  paic]  for  at  once  if  not  furnished  by  the  pupil  him- 

self.    In  filling  this  sheet,  all  the  items  which  could  possibly  be 


1  Since  the  handling  of  money  by  the  storekeeper  is  inconvenient, 
the  best  mode  of  securing  payment  for  broken  apparatus  and  for  non- 
returnable  materials  is  to  require  a  deposit  with  the  treasurer  of   the 
institution.     In  exchange  for  this  the  pupil  receives  a  breakage  ticket 
arranged  so  that  the  storekeeper  may  cut  off  the  value  represented  by 
each  transaction.     Any  balance  is  redeemed  at  the  end  of  the  year  after 
the  set  of  apparatus  has  been  turned  in  and  checked  up. 

2  The  Chicago     Laboratory   Supply  &   Scale   Co.  makes   a  special 
business  of  this  renovation. 


THE  LABORATORY 


197 


OUTFIT  FOR  GENERAL  CHEMISTRY  STUDENT. 


Laboratory Desk  No Locker  No.. 


Date- 


190 


ARTICLES  RETURNABLE.  —  The  articles  on  the  following  list  are  loaned  to 
the  student  and  they  must  be  returned  at  the  end  of  the  course  clean,  dry,  and 
in  good  condition.     If  any  article  is  observed  to  be  missing,  broken,  or  in  poor 
condition,  report  same  to  storekeeper  immediately  ;  and  if  any  such  article  can- 
not be  replaced  at  store-room,  a  line  should  be  drawn  through  the  name  of  article, 
for  no  allowance  will  be  made  after  sheet  is  signed.     Other  supplies  may  be  had 
as  needed  at  store-room,  where  posted  rules  should  be  read.     After  checking  this 
list  carefully,  sign  your  name  in  full  and  return  this  sheet  to  store-room  as 
soon  as  possible. 

Sand  Bath       
Pneumatic  Trough  

@ 

•So 
•45 
•25 

.10 

.20 

•45 
•45 
.06 

.20 

•35 

.12 

•25 

!o8 
1.50 
.10 

.20 
.12 
.12 
.10 
•IS 
.18 

•35 
•57 

.05 

Burette,  50  c  c  . 

@ 

$  -75 

•So 
.48 

.10 

.14 

.18 
.07 

•75 
.06 
.08 
.09 

•45 

.02 

'.06 
.OI 

•45 

1.  00 

•05 
.10 
.26 
•03 
.06 
.10 
.08 
.10 
•25 

•M 
•5° 
•So 

Graduated  Cylinder,  100  c.c.    . 

Iron  Stand,  small     
Iron  Rings,  3  sizes  
Clamp  Holder     
Burette  Clamp     
Universal  Clamp,  small    .     .     . 

Flask,  500  c.c  
Distilling  Flask,  30  c.c.  .     .     . 

Hofmann  Screw  Clamp     .     .     . 
Crucible  Tongs,  iron     .... 
Deflagrating  Spoon      .... 
Iron  Crucible  

Funnel,  75  mm  
Funnel,  100  mm  
Funnel  Stand     
Squares  of  Glass,  5X5  cm.     . 
Side  Neck  Test  Tubes    .     .     . 
Hard  Glass  Test  Tubes  .     .     . 
i     Test  Tubes,  130  mm.       .     .     . 
i     Test  Tubes,  180  mm  
Test  Tube  Rack 

Test  Tube  Holder   

Set  Weights         

Horn  Spatula  
Sponge  .     .     

Thermometer     
Thistle  Tube      
Hard  Glass  Tube,  10  inches    . 
Marchand's  CaCl,  Tubes    .     . 
Watch  Glass,  58  mm.      .     .     . 
Watch  Glass,  75  mm.      .     .     . 
Watch  Glass,  100  mm.     .     .     . 
File,  round    
Cork  Borer    

Porcelain  Crucible,  No.  o      .     . 
Evaporating  Dish,  No.  oo     .     . 
Evaporating  Dish,  No.  i.      .     . 
Evaporating  Dish,  No.  3  ... 
Porcelain  Mortar      .     .     . 
Nest     Beakers,      without     lip, 

$8  t&  A  1*3  T6S 

Bottles,  Narrow  Mouth,  250  c.c. 
Bottles,  Wide  Mouth,  250  c.c.  . 

Pair  Shears   

Clay  Triangle     
Gas  Tubing,  2  feet      .... 
Desk  Key  and  Padlock,  No.  — 
Locker  Key  and  Padlock,  No.  — 

Rubber  Stopper,  2-holed  .     .     . 

Local  address- 
Home  address- 


(Sign  here). 


ARTICLES  NON-RETURNABLE.  —  The  articles  on  the  following  list  must  be 
paid  for  at  once,  with  Chemical  Laboratory  breakage  ticket,  which  must  be  ob- 
tained from .  The  student  may  return  any  of  these  articles  when  he 

takes  the  desk,  if  he  already  has  them,  or  if  he  cares  to  get  them  elsewhere^ 


4     08 

3 

*     02 

06 

5   Feet  Glass  Tubing  . 

5  Feet  Glass  Redding     . 

4  Sheets   Filter   Paper,  No.    595, 

.05 

Total   

.48 

Date. 


198  THE  LABORATORY 

furnished  for  use  in  general  chemistry  have  been  included. 
Many  of  the  articles,  while  adding  to  the  convenience  of  the 
worker,  or  of  the  teacher,  as  in  the  case  of  the  weights,  may  be 
omitted,  in  order  to  save  expense,  without  damage  to  the  effec- 
tiveness of  the  work.  Indeed,  all  the  ordinary  purposes  of  the 
secondary  school  course  may  be  served  by  a  list  little  more  than 
half  as  long.  Another  much  smaller  form  may  be  used  when 
single  articles  are  obtained  from  the  store-room.  These  signed 
slips  being  filed,  the  location  of  the  various  pieces  of  apparatus 
is  always  readily  ascertainable,  and  the  responsibility  of  some 
pupil  for  their  return  is  fixed. 

The  teacher,  unless  his  class  is  an  exceedingly  small  one, 
should  not  be  burdened  with  the  task  of  attending  to  the  store- 
room. His  place  is  in  the  laboratory,  and  his  presence  can 
never  be  dispensed  with  for  a  moment.  The  loss  will  be  not 
so  much  to  the  teacher  as  to  the  efficiency  of  his  work.  An 
attendant  for  the  few  hours  during  which  the  laboratory  is  most 
in  use  will  probably  not  be  difficult  to  find. 

The  store-room  should  contain  a  key-board  for  the  keys  of 

all  desks,  lockers,  and  rooms  in  the  building,  unless  this  is  kept 

in  the  teacher's  private  room.     It   is  convenient 

also  to  have  in  it  some  articles  which  are  useful  in 

preparing  the  materials  used  in  the  laboratory,  such  as  a  pair 

of  tinner's  shears,  an  iron  mortar,  and  sieves  with  meshes  of 

various  sizes. 

In  the  matter  of  apparatus,  the  chief  necessity  is  to  have  an 
ample  supply  of  the  smaller  articles  which  are  most  used. 
Sources  of  Expensive  pieces  of  apparatus  can  always  wait  until 
Apparatus.  the  stock  of  the  other  more  necessary  articles  has 
reached  a  sufficient  size.  Most  of  our  glass  apparatus  is  made 
in  Germany  or  Bohemia,  but  recently  the  manufacture  of  very 
good  articles  at  reasonable  prices  has  been  begun  by  Whit- 
all,  Tatum  &  Co.,  of  Philadelphia.  In  ordering  apparatus  for 
general  chemistry,  care  should  be  taken  to  secure  flasks  with 
relatively  wide  mouths,  and,  if  possible,  to  have  the  glass  tubing 
and  the  stems  of  thistle  tubes,  etc.,  all  of  the  same  size,  in  order 


THE  LABORATORY  199 

that  constant  boring  of  new  corks  may  be  avoided.  In  general, 
apparatus  of  thin  glass  should  be  preferred.  Clamps,  burners, 
and  other  hardware  convenient  in  form  and  economical  in  price 
are  made  by  the  Chicago  Laboratory  Supply  &  Scale  Co.1 

Unless  very  large  quantities  are  needed,  chemicals  may  be 
bought  without  disadvantage  in  this  country.     Baker  &  Adam- 
son  of  Easton,  Pennsylvania,  make  chemically  pure 
articles  for  analytical  work.     Except  in  the  case  of 
the  common  acids,  and  a  few  materials  which  may  be  bought  of 
a  wholesale  grocer,  it  is  better  to  buy  chemically  pure  materials 
for  all  purposes. 

The  teacher  of  chemistry  must  be  a  person  who  is  not  simply 
interested  in  learning,  but  must  be  willing  to  give  a  good  deal 
of  time  to  the  management  of  the  material  equip-   careof 
ment  of  his  department.     The  utmost  system  and  Equipment. 
order  which  circumstances  permit  should  always  be  maintained. 
Articles  of  metal  should  be  watched  to  see  that  they  do  not 
corrode,  and  proper  measures  should  be  taken  for  their  pro- 
tection if  the  fumes  inseparable  from  the  laboratory  seem  to 
have  reached  them.3 

While,  for  the  reasons  stated  at  the  opening  of  this  chapter, 
a  good  equipment  is  exceedingly  desirable,  it  should  not  be 
forgotten  that  much  may  be  accomplished  at  very  little  expense 
when  more  means  cannot  be  obtained.  The  teacher  is  more 
important  than  the  laboratory,  for  a  good  teacher  will  know 
how  to  use  and  improve  even  a  poor  equipment.  A  good 


1  The   following  are   amongst   the   prominent   dealers  who   furnish 
apparatus  and  chemicals  of   all  kinds :   Eimer  &  Amend,  New  York  ; 
Richards  &  Co.,  New  York;  Queen  &  Co.,  Philadelphia;  Henry  Heil 
Chemical  Co.,  St.  Louis  ;  Sargent  &  Co.,  Chicago ;  L.  E.  Knott  Apparatus 
Co.,  Boston ;  Bausch  &  Lomb,  Rochester.     The  catalogues  of  these  and 
other   firms,  which   are   usually  illustrated,  give   much   information   in 
regard  to  apparatus.     These  firms,  as  well  as  the  Chicago  Laboratory 
Supply  &  Scale  Co.,  undertake  duty-free  importation  of  apparatus  and 
chemicals. 

2  A  valuable  article  on  the  care  of  apparatus  by  Inspector  James  H. 
Gibson  is  published  by  the  University  of  the  State  of  New  York.     High 
School  Bulletin,  No.  i,  362-366. 


200  THE  LABORATORY 

deal  may  be  done  with  ordinary  deal  tables,  a  few  bottles,  and 
domestic  substitutes  for  some  apparatus.  Some  suggestions 
on  this  head  will  be  found  in  Cooke's  Laboratory  Practice,  9 
and  10. 

V.     Classroom  and  its  Fittings. 

This  room  will  probably  be  used  in  common  with  teachers 
of  other  sciences.  It  should,  therefore,  be  provided  with  a 
The  Lecture-  large  desk  on  which  there  shall  be  room  for  the 
Table.  apparatus  and  specimens  required  for  illustrating 

the  work  of  more  than  one  class.  The  top  of  the  desk  should 
be  for  the  most  part  perfectly  clear,  in  order  that  an  uninter- 
rupted view  may  be  had  of  everything  upon  it.  The  gas  and 
water  supply  may  run  along  the  under  side  of  the  edge  next  to 
the  teacher,  and  small  holes  through  the  top  opposite  the  various 
stop-cocks  will  furnish  means  of  making  connections  through 
the  use  of  rubber  tubes.  There  should  be  a  sink  at  one  end  of 
the  table,  at  least,  and  several  water  faucets  should  be  provided, 
one  being  used  for  the  attachment  of  a  water  pump  arranged 
so  as  to  produce  a  vacuum  or  to  furnish  compressed  air. 
Underneath  the  table  convenient  cupboards  and  drawers  for 
the  apparatus  used  in  demonstrations  will  be  required.  For 
most  purposes  a  pneumatic  trough  with  glass  sides,  so  that  every- 
thing may  be  visible,  is  preferable  to  one  lined  with  lead  and 
sunk  in  the  table.  Shelving  for  acids  and  other  chemicals 
should  be  placed  in  a  convenient  position.  The  hood,  which 
should  be  connected  with  the  ventilating  system,  may  be  placed 
behind  the  blackboard.  The  latter  can  be  raised  when  the 
hood  is  in  use.  Openings  in  the  table  provided  with  a  down 
draught  and  proper  means  of  securing  the  removal  of  gases 
generated  in  the  course  of  experiments  are  almost  indispensable. 
In  order  that  no  time  may  be  lost  in  preparing  the  apparatus 
for  demonstrations,  or  in  exhibiting  the  experiments,  no  con- 
veniences which  can  be  obtained  should  be  omitted. 

The  seats  may  be  placed  on  steps  three  feet  in  width,  and 
each  rising  six  or  eight  inches  above  the  one  in  front  of  it. 


THE  LABORATORY  2OI 

Chairs  with  tablets  facilitate  the  taking  of  notes.  The  windows 
should  be  provided  with  grooves  and  opaque  shades  in  order 
that  the  room  may  be  darkened  when  necessary,  Lecture 
and  some  arrangement  should  be  provided  for  the  Experiments, 
exhibition  of  charts.  Most  of  the  apparatus  used  in  demon- 
strations will  be  the  same  as  that  employed  in  the  laboratory, 
excepting  that  everything  must  be  on  a  larger  scale.  The 
nature  and  use  of  the  necessary  apparatus  is  described  and  the 
apparatus  itself  is  figured  in  the  works  of  Newth  and  Benedict 
already  mentioned  (cf.  p.  134).  The  more  important  special 
articles  will  be  a  number  of  cylinders  of  various  sizes,  chiefly 
used  in  experiments  on  gases,  large  test  glasses,  which  are  use- 
ful in  showing  precipitations,  and  Hofmann's  apparatus  for 
exhibiting  the  volumetric  composition  of  various  substances.1 
For  class  experiments  with  electricity,  the  storage  battery  is 
much  more  convenient  than  any  other,  and  is  in  the  end  much 
cheaper,  if  means  of  charging  it  is  available.  Seven  cells,  with 
plates  five  and  a  half  inches  square,  will  be  found  sufficient  for 
all  ordinary  experiments,  and  the  whole  of  these  will  not  always 
be  employed.  A  stereopticon  for  projecting  lantern  slides  and 
some  experiments  is  very  convenient.  The  growth  of  crystals, 
for  example  (ammonium  oxalate  is  a  good  substance),  is  diffi- 
cult to  make  clear  without  this  means  of  exhibiting  its  progress. 

VI.    Illustrative  Material. 

Charts  and  collections   of  various  kinds  add  much  to  the 
interest  and  value  of  the  instruction.     Articles  which  will  serve 
the  purpose  just  as  well,  however,  may  be  made  or 
picked  up  in  various  ways  if  a  little  trouble  is  taken. 
Charts,  for  example,  made  from   good   illustrations   in   books 
which  are  up  to  date,  will  be  better  in  many  cases  than  the 


1  Simplified  forms  of  this  apparatus  are  sold  by  the  L.  E.  Knott 
Apparatus  Co.,  Boston.  The  best  arrangement  for  demonstrating  the 
equality  of  the  volumes  of  hydrogen  and  chlorine  given  off  in  the  electrol- 
ysis of  hydrochloric  acid  is  that  devised  by  Lothar  Meyer,  and  figured 
in  the  BERICHTE  D.  DEUTSCH.  CHEM.  GESELL.,  XXVII.  (1894),  850. 


202  THE  LABORATORY 

antiquated  and  clumsy  productions  which  are  still  sold.  Fre- 
quently a  pupil  will  be  found  who  has  talent  for  this  kind  of 
thing,  and  the  collections  of  the  school  may  be  enriched  with- 
out much  expense  through  his  assistance.  They  should  be 
made  on  some  material  which  will  not  be  damaged  by  handling, 
such  as  stout  tracing  linen,  or  paper  backed  with  linen. 

A  list  of  the  elements  with  their  atomic  weights,  compiled 
from  the  latest  data  by  F.  W.  Clark  (O=  16),  mounted  on  linen 
measuring  41"  X  61",  is  sold  by  Eimer  &  Amend  at  $2.  A 
similar  chart  of  the  periodic  system,  using  the  same  data, 
measuring  58"  X  42"  is  obtainable  at  the  same  price  from  the 
same  firm.  An  excellent  series  of  twenty-four  Chemical  Lecture 
Charts  is  published  by  Sampson,  Low,  Marston  &  Co.,  London. 
They  are  mounted  on  linen,  measure  40"  X  30"  and  cost  about 
$13.  They  include  the  plant  employed  in  many  chemical  in- 
dustries, and  some  illustrations  of  theoretical  matters,  such  as 
curves  of  solubility  and  the  apparatus  for  measuring  freezing- 
point  depressions.  A  set  of  twelve  charts  illustrating  industrial 
processes,  mounted  on  linen  and  measuring  170  X  125  cm. 
is  sold  by  Kaehler  &  Martini,  Berlin,  at  20.50  marks.  Some 
other  charts  are  mentioned  in  Eimer  &  Amend's  catalogue. 

The  teacher  will  find  it  convenient,  frequently,  to  prepare 
charts  illustrating  his  own  way  of  presenting  the  subject.  A 
list  of  the  metals  in  the  order  of  the  electro-motive  force  they 
show  when  arranged  in  conjunction  with  some  other  metal  in  a 
battery,  known  also  as  the  order  of  solution  tension,  if  hung  in 
the  classroom  will  find  frequent  application.1  This  order  rep- 

1  This  order  is  not  the  same  as  that  of  the  old  list  of  Berzelius,  which, 
although  hopelessly  out  of  date,  still  appears  in  some  works,  but  is  the 
result  of  modern  electro-chemical  (cf.  Le  Blanc,  Electro-Chemistry,  chapter 
VI.)  investigation.  Omitting  the  less  common  metals,  and  arranging 
the  others  in  order  of  decreasing  solution  tension,  it  is  as  follows  :  — 

Alkali  metals  Nickel  Bismuth 

Alkaline-earth  metals  Tin  Antimony 

Magnesium  Lead  Mercury 

Aluminium  Hydrogen  Silver 

Manganese  Copper  Platinum 

Zinc  Arsenic  Gold 
Iron 


THE  LABORATORY  203 

resents  at  once  the  tendency  of  the  element  to  form  ions,  the 
potential  it  acquires  when  placed  in  a  solution  of  one  of  its  salts, 
and  its  chemical  activity,  all  in  decreasing  order.  Thus  each 
metal  displaces  those  following  it  when  placed  in  a  solution  of 
any  salt.  Note  the  place  of  hydrogen.  The  metals  before  it( 
displace  this  gas  from  water  and  dilute  acids,  those  following  it 
do  not.  The  latter  are  found  free  in  nature,  while  the  former,  if 
they  existed,  would  eventually  become  oxidized  by  replacing  the 
hydrogen  of  water  or  weak  acids.  The  stability  of  the  oxides 
is  exhibited  also  in  some  measure.  As  far  as  manganese,  they 
are  not  completely  reducible  by  hydrogen ;  after  manganese, 
they  are  easily  reducible.  The  stability  of  other  compounds 
under  the  influence  of  heat  follows  approximately  the  same 
order.1 

Portraits  of  chemists  of  historical  prominence  are  attractive 
additions  to  the  classroom,  and  frequently  the  remembrance  of 
important  matters  in  chemistry  will  be  assisted  by 
association  with  the  appearance  of  the  man.  The 
NATURE  series  (London  and  New  York,  Macmillan)  includes 
some  very  artistic  likenesses,  although  they  are  perhaps  too 
small  for  use  in  a  large  room.  Kaehler  &  Martini  publish  a 
series  of  portraits  including  forty-eight  scientific  men,  with  bio- 
graphical text  by  Siebert  (size  29  X  39  cm.).  Portraits  of  Hof- 
mann  and  Victor  Meyer  suitable  for  framing  may  be  obtained  of 
the  Pharmaceutical  Review  Publishing  Co.,  Milwaukee. 

In  this  connection  it  may  be  pointed  out  that  photographs 
made  by  the  teacher,  or  some  friend,  from  actual  objects  of  chem- 
ical interest,  such  as  parts  of  chemical  factories,  may 

Photographs. 

be  enlarged  or  made  into  lantern  slides  and  furnish 
a   valuable    means  of  illustrating  many  things.     Many  of  the 
charts  and  illustrations  in  books  are  so  diagrammatic  in  their 
nature,  not  to  say  so  completely  out  of  date  in  many  cases,  that 
they  give  an  exceedingly  inadequate  impression  of  the  chemical 

1  A  chronological  chart  exhibiting  certain  historical  data  is  given  by 
Tilden  (Hints  on  the  Teaching  of  Elementary  Chemistry,  42-43)  and  may 
be  found  useful. 


204  THE  LABORATORY 

industries  as  they  are.  Authentic  representations  of  the  real 
thing,  therefore,  have  great  value  in  holding  before  the  mind  of 
the  pupil  the  fact  that  chemistry  is  on  one  side  a  great  industrial 
reality.  They  also  assist  in  keeping  the  subject  in  touch  with 
matters  of  every-day  life  which  may,  in  many  cases,  have  more 
or  less  close  connection  with  the  future  business  of  some  of  the 
pupils.  It  is  needless  to  say  that  visiting  factories,  so  far  as  they 
are  accessible,  will  be  of  the  highest  value.  The  managers  are 
usually  willing  to  allow  a  teacher  to  take  his  class  to  visit  their 
plants,  and  will  usually  furnish  a  conductor  more  or  less  capable 
of  answering  questions  intelligently  and  explaining  the  machinery 
and  processes  used. 

The  illustration  of  classroom  work  by  exhibition  of  speci- 
mens of  minerals  is  also  desirable.  This  strengthens  the  link 
connecting  chemistry  both  with  geology  and  with 
industry.  Good  specimens  can  frequently  be  found 
by  the  teacher  or  obtained  as  gifts.  They  may  also  be  pur- 
chased from  many  dealers.  Large  cabinet  specimens  are  not 
required.  The  most  instructive  specimens  to  purchase,  when 
limited  means  only  are  available,  are  single  crystals  showing 
common  and  typical  forms  of  the  various  substances.  These 
may  be  obtained  in  almost  all  cases  for  ten  or  fifteen  cents  each. 
A  set  of  typical  minerals  fulfilling  these  requirements  need  not 
be  extensive.1 


1  List  of  36  Minerals  which  furnish  good  crystals,  are  important  ores, 
or  are  conspicuous  constitutents  of  rocks  [cr.  (=  crystal)  and  mass.  (  = 
massive)  indicate  the  best  forms  for  our  purpose]. 

Copper  (ramifying)  Malachite   (pseudom.  from   cuprite, 

Arsenic  (scales)  cr.) 

Sulphur  (cr.)  Selenite  (Gypsum,  CaSO4,  2H2O,  cr.) 

Halite  (NaCl,  cr.)  Barite  (BaSO4,  cr.) 

Fluorite  (CaF2,  cr.)  Corundum  (A12O3,  cr.) 

Cryolite  (3NaF,  A1F3,  mass.)  Specularite  (Fe2O3,  cr.) 

Calcite  (CaCO3,  cr.)  Haematite  (Fe2O3,  mass.) 

Dolomite  (CaMg(CO3)2,  cr.)  Limonite  (Fe2O3)  hydrated.  Pseu- 

Siderite  (FeCO3,  cr.)  dom.  from  pyrite,  cr.) 

Arragonite  (CaCO3,  cr.)  Pyrolusite     or     manganite     (MnO.2, 

Malachite  (CuCO3,  basic  and  hy-         hydrated,  mass.) 
drated,  mass.)  Magnetite  (Fe3O4,  cr.) 


THE  LABORATORY  205 

One  of  the  subjects  strangely  neglected  both  in  schools  and 
colleges  in  this  country  is  the  study  of  crystals.  Their  treatment 
here  is  in  marked  contrast  to  that  in  Germany, 
where  a  pretty  extensive  knowledge  of  crystallog- 
raphy is  required  of  teachers  in  secondary  schools,  and  a  large 
part  of  the  work  in  science 1  deals  with  the  study  of  crystalline 
forms  geometrically  and  with  physical  crystallography.  It  is 
not  suggested  that  the  time  available  in  the  secondary  school 
course  is  likely  to  permit  the  introduction  of  much  of  this  subject. 
Some  trouble  should  be  taken,  however,  to  give  the  pupils  an 
intelligent  knowledge  of  how  crystals  grow,  and  of  some  of  the 
common  forms.  The  chemist  depends  very  largely  on  the 
making  of  crystals  for  purification,  and  on  the  form  of  them  for 
identification  in  his  work,  and  both  of  these  features  appear  in 
elementary  chemistry,  whether  particular  attention  is  paid  to 
them  or  not.  The  pupils  will  always  take  great  interest  in 
growing  large  crystals  for  themselves,  and  will  learn  much  from 
the  exercise.  Common  alum  and  chrome-alum  give  beautiful 
octahedra;  nickel  sulphate  (NiSO4,  4H2O),  illustrates  the 
square  prismatic  system;  cupric  sulphate  (CuSO4,  5H2O),  the 
asymmetric  ;  double  potassium  cupric  sulphate,  made  by  mixing 
the  two  salts  in  equi-molecular  proportions,  the  monoclinic,  etc. 
Models  made  of  wood  or  of  cardboard  to  show  the  com- 
mon forms  on  a  large  scale  may  be  purchased  or  made  very 
readily. 

Chromite  (FeCr2O4,  cr.)  Garnet  (cr.) 

Cassiterite  (Sno2,  cr.)  Apatite  (cr.  Ontario) 

Quartz  (SiO2,  cr.)  Cyanite  (mass.  Illustrates  two  hard 

Sphalerite  (ZnS,  cr.)  nesses) 

Stibnite  (Sb2S3,  cr.  Japan)  Analcite  (cr.) 

Cinnabar  (HgS,  mass.)  Hornblende  (cr.) 

Galena  (PbS,  cr.)  Orthoclase  (cr.) 

Pyrite  (FeS2,  cr.)  Topaz  (cr.  Japan) 

Zircon  (cr.) 

Prominent  dealers  in  minerals  are  G.  L.  English  &  Co.,  New  York ; 

E.   A.   Foote,   Philadelphia ;  Roy   Hopping,   New   York ;   and   Ward, 
Rochester. 

1  See  Russell,   German  Higher  Schools,  chapter  XVIL,  particularly 
p.  364. 


206  THE  LABORATORY 

VII.    The  Teacher's  Private  Room. 

A  private  work-room  should  be  provided  for  the  teacher  in 
order  that  he  may  have  a  place  in  which  to  pursue  his  own 
work  undisturbed.  He  may  there  try  new  experiments  for  de- 
monstrations, and  perhaps  devise  better  means  of  illustrating 
important  points  in  chemistry  for  himself.  He  will  also  thus  be 
enabled  to  continue  his  study  of  the  subject  by  experimental 
work,  for  no  one  can  afford  simply  to  rest  upon  what  he  knows  : 
such  a  course  must  really  involve  retrogression.  If  his  appli- 
ances and  time  permit,  and  his  previous  training  has  been  suffi- 
cient, this  room  will  furnish  opportunity  for  carrying  on  research 
in  some  direction. 

The  room,  like  the  laboratory,  should  have  connections  for 
gas,  water,  and  electricity,  and,  in  addition  to  the  usual  ap- 
paratus, should  perhaps  be  furnished  with  a  bench  fitted  with 
a  small  anvil  and  vice,  and  provided  with  a  few  tools. 


CHAPTER   VIII 

THE  TEACHER,  HIS  PREPARATION  AND  DEVELOPMENT 

Nichols,  E.  L.  Paper  on  the  Training  of  Science  Teachers  for  Sec- 
ondary Schools,  and  discussion  thereon.  High  School  Bulletin  No.  7. 
Albany,  N.  Y.,  The  University  of  the  State  of  the  New  York.  1900. 
Pp.  630-650. 

Russell,  J.  E.  German  Higher  Schools.  London  and  New  York, 
Longmans,  Green  &  Co.  1899.  Chapters  XVIII.  and  XIX. 

Bolton,  F.  E.  The  Secondary  School  System  of  Germany.  New 
York,  D.  Appleton  Co.  London,  Edward  Arnold.  1900.  Chapter  II. 

THIS  chapter  naturally  divides  itself  into  three  parts  which 
treat  of  the  training  of  the  teacher,  the  best  means  for  securing 
his  continued  development,  and  the  literature  which  will  be 
most  useful  in  connection  with  the  latter.  It  would  be  useless 
to  discuss  the  qualities  of  sympathy,  tact,  alertness,  force  of 
character,  etc.,  which  are  indispensable  in  the  teacher  of  chem- 
istry as  in  the  teacher  of  any  other  subject.  These  depend 
largely  on  the  natural  aptitude  of  the  aspirant  to  the  profession 
of  teaching.  It  is  rather  the  strictly  professional  part  of  the 
preparation  of  the  teacher  which  primarily  concerns  us. 

I.     The  Training  of  the  Teacher. 

LThe  indispensable  acquisition  of  the  teacher  is  a  well-rounded 
and  sound  knowledge  of  the  subject.  Nothing  can  possibly 
make  up  for  the  absence  of  a  preparation  which  will  give  thisj 
It  is  to  be  feared  that  the  attempt  is  often  made  to  teach  chem- 
istry without  this  prerequisite.  Often,  as  we  have  already  re- 
marked, a  teacher  who  is  conscious  of  incompetence  is  required 
by  the  principal  of  his  school  to  teach  this  subject,  simply  be- 
cause its  representation  in  the  curriculum  is  desired.  Often  the 


208  THE    TEACHER 

student  in  a  college  whose  curriculum  is  of  the  old  stamp  does  not 
discover  until  late  in  his  course  the  natural  bent  which  he  may 
possess  towards  physical  science.  He  may  thus,  while  lacking 
the  proper  preparation,  find  that  his  taste  leads  him  in  the 
direction  of  science,  if  his  inclination  or  circumstances  induce 
him  to  become  a  teacher  at  all.  Often,  too,  the  college  student 
may  have  pursued  the  study  of  chemistry  pretty  extensively 
during  his  course,  but  the  nature  of  the  instruction  may  have 
been  such  that,  in  spite  of  his  acquaintance  with  many  phases 
of  the  subject,  he  is  little  better  prepared  to  teach  it  than  the 
members  of  the  two  other  classes.  For  these  and  many  other 
reasons,  it  is  to  be  feared  that  the  teachers  of  chemistry  in  our 
secondary  schools,  as  a  class,  are  not  so  thoroughly  fitted  for 
their  work  as  they  should  be.  Yet,  as  Professor  Bennett  says, 
we  cannot  "  pass  judgment  on  the  mass  of  the  incompetent. 
They  are  almost  without  exception  men  and  women  of  charac- 
ter, of  serious  and  earnest  purposes,  and  faithful  even  to  the 
detriment  of .. their  health  in  the  performance  of  their  tasks. 
They  are,  nevertheless,  endeavouring  to  achieve  the  impossible, 
—  to  perform  a  work  involving  the  employment  of  large  re- 
sources without  ever  having  secured  the  necessary  preparation." 
(_The  first  constituent  of  this  necessary  knowledge  of  chem- 
istry is  general  chemistry.!  If  we  ask  what  the  second  ingredient 
must  be,  we  should  be  compelled  to  say  again  gen- 

Generai^hem  cra^  cner™stry>  anc^  tne  same  answer  must  be  given 
istry  the  at  every  repetition  of  the  question,  fit  is  a  knowl- 
Prime  Essen-  edge  of  the  science  as  a  whole  and  not  of  any 

special  section  of  it  which  will  count  in  elementary 
instruction.  \  Only  in  so  far  as  other  branches  may  contribute 
to  this  knowledge  are  they  to  be  considered  a  specially  desir- 
able part  of  the  training  of  the  teacher  of  elementary  chemistry. 
It  is  a  delusion  to  suppose  that  general  chemistry  can  be  dis- 
posed of  in  three  months,  and  that  the  next  thing  to  be  done  is 
to  study  qualitative  analysis.  A  whole  year  of  general  chem- 
istry will  not  confer  anything  like  sufficient  knowledge  of  the 
subject  for  our  purpose. 


THE    TEACHER  209 

Taking  the  matter  in  detail,  we  require  first  an  introductory 
course.  This  must  be  thoroughly  sound  and  fairly  extensive. 
How  rare  courses  possessing  these  characteristics  First  Tear  of 
are,  only  those  who  have  studied  the  instruction  Preparation. 
in  many  institutions  know.  General  chemistry  cannot  be 
taught  by  a  public  analyst  in  his  spare  moments,  by  a  phy- 
sician with  limited  professional  practice,  or  by  a  "  sticket 
minister"  with  a  taste  for  science.  The  instructor  must  be  a 
man  himself  engaged  in  productive  chemical  work  and  thor- 
oughly abreast  of  the  times.  He  must  be,  so  to  speak,  a 
self-luminous  body,  for,  the  more  he  plays  the  part  of  a  re- 
flector or  a  refractor  of  borrowed  information,  the  less  truly 
will  the  image  represent  the  nature  of  the  science.  The  intro- 
duction should  be  a  year  in  length,  it  should  be  accompanied 
by  much  laboratory  work,  and  its  whole  scope  should  be  much 
greater  than  that  of  the  corresponding  course  in  the  secondary 
school. 

Beyond  this,  the  knowledge  of  the  subject  must  be  deepened 
in  various  directions.  More  acquaintance  with  the  ordinary 
facts  of  the  science,  more  knowledge  of  theoretical  and  physi- 
cal chemistry  by  study  and  by  practical  work,  more  ability  to 
handle  the  literature  of  the  subject,  and  a  far  broader  grasp  of 
the  ramifications  of  the  science  in  the  directions  of  industry, 
agriculture,  geology,  physiology,  and  hygiene  are  needed.  And 
all  this  will  be  valueless  if  the  theory,  the  literature,  and  the  ap- 
plications are  not  treated  in  a  thoroughly  modern  manner. 

It  might  be  suggested,  as  a  tentative  plan,  that  the  second 
year,  following  general  chemistry,  should  begin  with  a  study  in 
classroom  and  laboratory  of  such  topics  as  chemical  ... 
equilibrium,  the   methods   of  measuring  chemical  General Chem- 
affinity,  and  the  boiling  point,  freezing  point,  elec-       •y' 
trolysis,  and  other  properties  of  solutions  which  are  of  such  im- 
portance in  the  chemistry  of  qualitative  analysis.     Without  these 
preliminaries,  the  last-named  subject  can  contribute  nothing 
worth  mentioning  to  the  student's  knowledge  of  general  chem- 
istry.    This  might  be  followed  by  an  elementary  study  of  quali- 


210  THE    TEACHER 

tative  analysis  itself,  care  being  taken  to  use  the  light  which  the 
recent  study  of  solutions  has  thrown  upon  their  chemical  nature 
in  explaining  the  rationale  of  the  processes  used,  and  in  general 
so  to  employ  the  subject  as  to  deepen  and  broaden  the  pupil's 
knowledge  of  general  chemistry  as  far  as  possible.1  Following 
this,  exercises  in  the  determination  of  molecular  weights,  the 
measurement  of  equivalents  and  combining  weights,  in  which 
the  refinements  of  quantitative  analysis  are  employed  and  the 
results  are  used  for  working  out  atomic  weights,  will  probably 
occupy  the  remainder  of  the  year.2  Throughout  the  course, 

1  OstwalcTs  Scientific  Foundations  of  Analytical  Chemistry  (Macmillan) 
shows  in  detail  how  the  operations  of  analysis  may  be  rationalized. 

2  Experience  shows  that  students  gain  but  a  feeble  grasp  on  the  sci- 
ence until  they  have   done  some  exact  quantitative  work.     It  is  prefer- 
able on  many  grounds  even  to  begin  the  second  year  with  three  months 
of  quantitative  analysis,  to  follow  this  with  theoretical  chemistry,  and  to 
place  elementary  qualitative  analysis  last.     Of  course  the  benefit  derived 
from  the  reversal  of  the  ordinary  arrangement  will  depend  entirely  on  the 
method  and  spirit  of  the  instruction. 

Quantitative  analysis  should  be  used  to  train  the  prospective  teacher 
in,  and  make  him  familiar  with  that  accuracy  of  work  and  refinement  of 
method,  which  are  not  only  characteristic  of  the  subject-matter  of  the 
science,  but  which  also,  in  some  shape  or  other,  are  the  ultimate  basis  of 
all  advance  in  the  knowledge  of  chemistry  by  experimental  methods. 
Such  training  is  not  only  necessary  if  the  teacher  is  to  add  to  our  knowl- 
edge of  chemistry  (see  p.  216),  but  is  equally  indispensable  if  he  is  to  un- 
derstand, without  hiatus  or  distortion,  how  our  knowledge  has  been  de- 
veloped (seep.  77).  To  achieve  these  ends  the  quantitative  analysis 
should  not  only  deal  with  the  separation  and  determination  of  a  certain 
number  of  bodies,  but  should  develop  as  far  as  possible  a  sense  of  the 
ultimate  exactness  and  rigidity  of  the  proofs  of  those  theories  to  which 
in  the  previous  work  in  general  chemistry  (and,  when  the  old  order  was 
followed,  qualitative  analysis)  constant  reference  has  been  made  (see 
p.  72). 

At  the  same  time  the  previously  acquired  knowledge  of  chemistry  in 
the  broader  view  (general  chemistry,  as  we  have  called  it)  should  be 
used  and  increased  as  far  as  possible,  e.g.,  by  exact  determinations  of 
combining  weights,  by  testing  the  law  of  the  conservation  of  mass,  and 
by  applying  the  laws  of  chemical  equilibrium  to  the  methods  used. 
Certain  phases  of  general  chemistry  can  be  considered  profitably  at  some- 
what greater  length  at  this  stage,  e.g.,  isomorphous  mixtures,  the  prep- 
aration of  chemically  pure  substances,  and  the  growth  of  crystals  of 
difficultly  soluble  salts  such  as  barium  sulphate. 

Finally,  in  quantitative  analysis  students  should  take  up  some  prob- 


THE    TEACHER  211 

the  reading  in  various  works  of  reference,  in  selected  original 
papers,  and  along  historical  lines,  should  be  arranged  with  great 
skill,  so  as,  on  the  one  hand,  to  strengthen  the  pupil's  grasp  on 
the  topics  taken  up  in  the  laboratory,  and,  on  the  other,  to  fill 
out  the  gaps  between  these  topics,  and  render  the  whole  study 
more  symmetrical.  Indispensable  as  extensive  reading  is  at 
this  stage,  it  is  almost  wholly  neglected  in  most  institutions  at 
the  present  day.  It  is  left  to  the  initiative  of  the  pupils  who 
have  special  interest  in  the  subject,  precisely  at  the  time  when 
guidance  and  stimulus  from  the  teacher  are  most  needed. 

The  difficulty  in  endeavouring  to  give  a  course  like  the  above 
is  that  no  text-books  or  laboratory  outlines  of  the  sort  which 
would  harmonize  with  this  ideal  are  available,  excepting  per- 
haps in  organic  chemistry. 

The  third  year  of  work  will  contain  organic  chemistry  and 
inorganic   preparations  on  the  lines   of  Lengfeld's   Inorganic 
Preparations l    (Macmillan).      The   final   prepara-  organic 
tions   made   should  be  of  a  more  difficult   order,   Chemistry, 
to  the  end  that  the  pupil,  by  examination  of  the  literature  for 
himself,  may  make  some  approach  to  realizing  the  conditions 
of  original  research.     During  this  year  reading  and   inorganic 
study  are    again  indispensable.     Seminar  work   in   Preparations. 
which  reports  on  recent  discoveries  are  presented,  and  topics 
of  vital  interest  in  the  point  of  view  of  general  chemistry  are 
discussed,  will  serve  for  reviewing  and  deepening 
the  knowledge  of  the  subject.     There  is  far  too 
much  so-called  instruction  in  chemistry  in  our  higher  institutions 


lems  from  the  standpoint  of  semi-original  investigation  with  the  rigid 
criteria  applied  in  real  research. 

Work  having  these  characteristics  serves  to  clinch  the  impression 
made  when  the  corresponding  topics  were  discussed  in  the  introductory 
course.  On  the  other  hand,  the  common  kind  of  quantitative  analysis, 
which  devotes  itself  exclusively  to  technique,  and  can  be  fairly  defined  by 
the  number  of  determinations  it  includes,  is  of  little  value  at  any  stage. 
It  may  give  some  mechanical  skill,  but  it  will  teach  no  chemistry. 

1  F.  H.  Thorp,  Inorganic  Chemical  Preparations  (Ginn  &  Co.),  and 
Erdmann-Dunlap,  Introduction  to  Chemical  Preparation  (John  Wiley  & 
Sons),  are  similar  works. 


212  THE    TEACHER 

which  consists  solely  in  technical  guidance  of  experimental 
work,  and  neglects  entirely  the  development  of  the  scientific 
knowledge  of  the  pupils.  Experimental  work  without  reading, 
and  exercises  which  call  for  no  thought,  are  as  useless  as  food 
without  the  intervention  of  the  digestive  fluids. 

It  need  not  be  added  that  during  this  time  physics  and 
mineralogy,  at  least,  and  if  possible  other  sciences,  should  be 
pursued,  not  only  on  account  of  their  indispensability  as  sources 
of  illustration  in  the  teaching  of  chemistry,  but  also  because  the 
future  teacher  may  have  to  give  instruction  in  some  of  them. 
The  other  studies  should  include  a  sufficient  amount  of  German 
to  give  a  reading  knowledge,  since  it  is  difficult  to  pursue  the 
study  of  chemistry  without  reference  to  articles  and  books  in 
this  language. 

It  seems  to  me  that  three  years,  properly  spent,  will  furnish  a 
knowledge  of  the  science  which,  considering  the  demands  of 
the  secondary  school,  will  be  approximately  equivalent  to  that 
expected  in  other  subjects.  The  time,  however,  must  be  spent 
as  largely  as  possible  in  acquiring,  adding  to,  and  throwing  side- 
lights upon  general  chemistry.  Long  courses  in  analysis,  while 
they  must  be  included,  at  some  stage,  in  the  training  of  techni- 
cal chemists  and  investigators,  are  a  misapplication  of  precious 
time  so  far  as  our  purpose  is  concerned.  This  adequate  train- 
ing cannot  be  obtained  quickly  or  without  expense.  It  will 
require  almost  continuous  work  throughout  the  college  course, 
or  an  equivalent  of  this. 

The  question  is,  where  can  the  teacher  in  training  secure  the 
needful  instruction.  Not  of  a  surety  in  the  departments  of 
The  Present  chemistry  of  our  colleges  and  normal  schools  as  at 

Condition         present  conducted.     The  chemical  curricula  of  our 

of  Higher 

instruction      higher  institutions,  largely  through  the  influence  of 

in  Chemistry.  tra(jjtion,  are  so  filled  with  a  mass  of  specialized 
work  in  stereotyped  grooves  that  proper  instruction  for  teachers 
is  difficult  to  obtain.1  Their  arrangements  seem  to  be  made  for 

1  For  a  highly  interesting  discussion  of  this  subject,  see  Professor 
Armstrong's  Presidential  Address  before  the  Chemical  Society  of  Lon- 


THE    TEACHER  21 3 

the  purpose  of  training  chemists  for  agricultural  stations  or  com- 
mercial work.  The  conventional  order  of  general  chemistry, 
followed  by  qualitative  and  then  quantitative  analyses,  is  unfortu- 
nate. The  two  latter  subjects,  as  ordinarily  taught  (cf.  pp.  173, 
210),  contribute  practically  nothing  to  the  student's  knowl- 
edge of  the  science  of  chemistry  in  the  broader  view.  They 
are  almost  always,  for  the  most  part,  purely  technical  applica- 
tions of  a  single  aspect  of  the  subject,  and  during  their  study 
so  much  general  chemistry  is  forgotten  that  the  student  really 
acquires  a  narrower  view  of  the  subject  in  some  respects  than 
he  had  at  the  end  of  the  first  year.  The  analyst  turned  out  by 
this  training  can  do  the  routine  work  of  a  factory.  His  stand- 
ing is  the  same  as  that  of  a  bookkeeper,  and  his  work  requires 
no  more  extensive  training.  His  preparation  does  not  fit  him 
to  assist  in  advancing  chemical  industry,  any  more  than  that  of 
the  mere  bookkeeper  fits  him  to  manage  an  extensive  business 
successfully.  The  student  who  intends  to  become  a  teacher  of 
chemistry  has  to  pick  up  the  nourishment  for  the  growth  of  a 
broad  knowledge  of  the  subject  from  what  must  be  admitted  to 
be  a  rather  sparse  vegetation  in  this  point  of  view,  and  it  is  at 
present  only  the  exceptional  student  who  gets  it.  I  should 
certainly  be  at  a  loss  to  mention  any  institution  in  which  an 
ideal  course  for  teachers  is  given.  Yet,  as  Professor  Nichols 
says,  in  his  admirable  paper  on  The  Training  of  Science  Teach- 
ers :  "  No  institution,  whether  it  calls  itself  normal  school,  col- 
lege, or  university,  that  does  not  offer  the  student  opportunities 
of  the  kinds  just  indicated  [Nichols'  course  in  physics  was  on 
the  same  lines  as  that  outlined  above  for  chemistry],  is  fitted  for 
the  training  of  the  modern  science  teacher.  No  institution,  the 
members  of  the  faculty  of  which  are  not  bonafide  men  of  science, 


don.  JOURNAL  OF  THE  SOCIETY,  XLV.  (1894),  361  ;  reprinted  in  NA- 
TURE, L.  211.  See  also  Professor  John  H.  Long's  address  on  the 
Teaching  of  Chemistry  in  the  Medical  Schools  of  the  United  States. 
SCIENCE  [N.  S.],  XIV.  360.  Mr.  Lachman,  in  an  address  on  the  Im- 
provement of  Instruction  in  Technical  Chemistry,  utters  some  very  sug- 
gestive criticisms  of  the  present  methods  and  sketches  a  substitute. 
JOUR.  Soc.  CHEM.  INDUSTRY,  XX.  (1901),  546. 


2/4  THE    TEACHER 

devoting  themselves  quite  as  seriously  and  continuously  to  re- 
search as  to  routine  teaching,  can  hope  to  produce  in  its  students 
those  qualities  and  habits  of  thought  that  ...  are  essential  to 
the  highest  type  of  teacher." 

II.     The  Development  of  the  Teacher  during  Professional  Life. 

The  teacher  cannot  afford  to  settle  down  and  dole  out  his 
instruction  from  the  slowly  petrifying  deposit  with  which  his 
college  provided  him.  He  must  follow  the  new  developments  of 
the  subject,  and  continually  change  his  mode  of  presenting  every 
part  of  it,  in  order  that  it  may  harmonize  with  the  best  thought 
of  chemists.  Not  only  this,  however,  but  he  must  continually  in- 
crease his  own  attainments.  The  best  preparation  always  seems 
to  have  been  wonderfully  meagre  compared  to  the  mass  of  knowl- 
edge which  we,  as  teachers,  find  indispensable  in  our  work. 

The  reading  of  the  latest  text-book  is  useful,  but  the  most 
productive  method  of  study  is  to  take  up  some  topic  of  inter- 
Whatto  est  and  pursue  it  to  its  limits.  A  subject  like  nitric 
Read>  acid  and  the  oxides  of  nitrogen,  for  example,  when 

studied  first  in  all  the  general  works,  then  in  the  larger  books 
of  reference,  and  finally  in  the  original  literature,  will  be  found 
exceedingly  interesting.  The  study  of  the  various  determina- 
tions of  the  ratio  of  hydrogen  to  oxygen  in  water,  in  spite  of 
the  somewhat  dry  aspect  which  the  mere  statement  of  the  subject 
presents,  will  be  found  truly  fascinating.  The  determinations 
of  the  atomic  weights  of  aluminium,  zinc,  and  other  elements, 
are  highly  instructive  on  account  of  the  precautions  employed 
in  their  execution.  These  are  mentioned  as  examples,  and  the 
catalogue  might  be  prolonged  almost  indefinitely  without  going 
outside  the  list  of  subjects  upon  which  many  important  papers 
have  been  published  in  the  English  language.1 

1  References  to  books  treating  fully  or  with  especial  clearness  of  many 
chemical  questions  will  be  found  scattered  through  the  present  work.  A 
large  number  are  given  in  Newell's  Teachers'  Supplement.  The  follow- 
ing are  a  very  few  references  to  important  and  interesting  original 
articles  in  English. 

Action   of  metals  on  nitric  acid.     Freer,  Inorganic  Chemistry,  chap- 


THE    TEACHER  21$ 

Not  only  is  the  reading  of  original  papers  easy  after  such 
preparation  as  the  examination  of  the  text-books  gives,  but, 
contrary  to  the  popular  impression,  it  is  vastly  more  interesting 
and  incomparably  more  valuable  than  the  study  of  books 
alone.  If  we  want  to  know  about  a  plant,  we  must  consider  the 
whole  structure,  and  the  whole  course  of  development  from  the 
seed  to  maturity.  The  structure  of  a  few  dead  chips  is  as  little 
enticing  or  useful  in  this  connection,  as  the  study  of  text-books 
is  in  giving  a  genuine  knowledge  of  what  constitutes  the  science 
of  chemistry.  Only  the  examination  of  the  literature  can  show 
us  the  growth  of  each  fragment  of  the  science  and  how  ad- 
ditions to  human  knowledge  of  permanent  value  are  really 
made.  The  atmosphere  of  the  text-book  suggests  the  museum 
or  the  tomb  to  one  who  has  breathed  the  air  of  the  workshop 
and  of  life  in  the  original  reports  of  the  investigator. 

ter  XXVI.  AM.  CHEM.  JOUR.,  XV.  71 ;  XVII.  18 ;  XVIII.  587  ;  XXI. 
378. 

Atomic  weight  of  oxygen.  Cooke  and  Richards,  AM.  CHEM.  JOUR., 
X.  81  and  191.  Keiser,  ibid.,  X.  249  ;  XX.  733.  Noyes,  ibid.,  XII.  441. 

Atomic  weight  of  zinc.  Morse,  AM.  CHEM.  JOUR.,  X.  311.  Clarke, 
ibid.,  III.  263. 

Molecular  weight  of  hydrogen  fluoride.  Mallett,  AM.  CHEM.  JOUR., 
III.  189. 

Persulphates.  Marshall,  JOUR.  CHEM.  Soc.,  LIX.  772.  JOUR.  Soc. 
CHEM.  INDUSTRY,  XVI.  No.  5. 

Nickel  carbonyl.  Mond,  Langer,  and  Quincke,  JOUR.  CHEM.  Soc., 
LVII.  750. 

Allotropic  forms  of  silver.  Carey  Lea,  AM.  JOUR.  OF  Sci.,  [3], 
XXXVII.  476.  Barus,  ibid.,  XLVIII.  451. 

Absence  of  chemical  action  in  absence  of  water.  Baker,  JOUR.  CHEM. 
Soc.,  LXV.  611.  Shenstone,  ibid.,  LXXI.  471. 

Argon.     Rayleigh  and  Ramsay,  AM.  CHEM.  JOUR.,  XVII.  225. 

Helium.     Ramsay,  JOUR.  CHEM.  Soc.,  LXVII.  684  and  1107. 

Urea  and  ammonium  cyanate.  Walker,  JOUR.  CHEM.  Soc.,  LXVII. 
746;  LXIX.  193;  LXXI.  489;  LXXVII.  21. 

Perchloric  anhydride.  Michael  and  Conn,  AM.  CHEM.  JOUR.,  XXIII. 
444. 

Adsorption.     Walker,  JOUR.  CHEM.  Soc.,  LXIX.  1334. 

Flame.  Smithells,  JOUR.  CHEM.  Soc.,  LXI.  (1892),  204;  LXVII. 
(1895),  I0495  NATU-RE,  XLIX.  (1893),  86,  also  correspondence  on  pp. 
100,  149,  171,  172,  198;  CHEMICAL  NEWS,  LXVI.  (1893),  J39»  I°o- 
Lewis,  CHEMICAL  NEWS,  LXV.  (1892),  112,  125;  LXVI.  (1893),  99. 


216  THE   TEACHER 

Reading,  however,  is  not  sufficient ;  there  should  be  con- 
tinual experimental  work  adapted  to  the  previous  training  of 
Experimental  tne  teacher.  Making  recently  discovered  corn- 
Work,  pounds,  and  repeating  new  ways  of  making  old 
ones,  will  furnish  opportunities  for  work  of  any  degree  of  ease 
or  difficulty.  The  persulphates,  nickel  carbonyl,  the  allotropic 
forms  of  metallic  silver,  and  many  other  interesting  bodies  can 
be  made  with  the  resources  of  any  laboratory.  Some  of 
Baker's  experiments  on  the  absence  of  chemical  union  in 
dry  materials  will  give  opportunity  for  the  use  of  experimen- 
tal skill.  If  the  teacher  lacks  preparation  for  this  kind  of  work, 
he  may  add  to  his  knowledge  by  a  systematic  course  of  experi- 
ments and  reading  in  inorganic  preparations,  in  organic  chem- 
istry or  in  some  of  the  experimentally  simpler  parts  of  physical 
chemistry,  such  as  the  observation  of  the  boiling  point  and  freez- 
ing point  of  solutions,  the  measurement  of  vapour  densities, 
etc.1 

For  the  teacher  who  has  the  necessary  qualifications,  the  very 
best  exercise  of  his  powers  will  be  in  making  simple  original 
investigations.  I  should  hesitate  to  mention  this 
if  it  were  not  that  Professor  Nichols 2  insists  upon 
it  as  an  indispensable  feature  in  the  life  of  every  teacher,  and 
that  Professor  Ganong,  in  his  Teaching  Botanist  (48),  makes 
a  strong  plea  of  the  same  kind.  It  is  well  known  that  the  time 
of  the  teacher  is  very  fully  occupied,  and  that  his  equipment  is 
often  far  from  adequate,  even  for  the  needs  of  elementary  in- 
struction. It  must  be  admitted,  however,  that,  as  Professor 
Nichols  explains  at  great  length,  these  objections  are  not  con- 
clusive. The  professor  in  the  college  or  university,  when  we 


1  Much  highly  instructive  work  of  a  kind  a  little  above  the  ordinary 
laboratory  course  in  general  chemistry  is  described  in  Muirand  Carnegie's 
Practical  Chemistry  (Cambridge  University  Press,  1887),  particularly  in 
Part  I.,  Chapters  XVI.,  XVIII. ;  Part  II.,  Chapters  IV.-VII. ;  Part 
III.,  Chapters  II.-IV.  Most  phases  of  physical  chemistry,  with  the  ex- 
ception of  the  theory  of  solutions,  are  illustrated  in  these  chapters. 

2  Loc.  cit.  See  also,  for  subjects  of  research  in  physics,  SCHOOL  SCIENCE, 
I.  10. 


THE    TEACHER  21J 

consider  the  burden  of  laboratory  teaching  and  of  executive 
work  which  he  must  carry,  is  on  the  average  no  better  off  than 
the  teacher  in  the  secondary  school,  and  he  is  expected  to 
pursue  research  continuously.  Nor  is  elaborate  outfit  or  ap- 
paratus necessarily  required.  There  are  problems,  possibly  of 
a  minor  nature,  which  can  be  solved  with  nothing  beyond  the 
material  used  in  teaching  elementary  chemistry,  unless  it  be 
a  balance.  Even  this,  however,  is  not  always  indispensable. 
Above  all,  we  must  remember  that  some  of  the  best  scientific 
work  has  been  done,  in  secondary  schools  as  well  as  in  colleges, 
by  men  who  had  neither  time  nor  appliances  which  would 
have  encouraged  us  to  expect  any  productive  work  whatever.1 

The  other  means  which  are  available  for  assistance  in  the 
development  of  the  teacher  may  be  mentioned  more  briefly.  It 
is  not  often  possible  for  him  to  take  graduate  work  Summer 
in  some  university,  but  the  summer  schools,  which  Schools, 
are  now  so  numerous  as  to  be  readily  accessible  to  every  one, 
are  taken  advantage  of  by  teachers,  in  some  instances,  to  so 
remarkable  an  extent  that  their  power  to  aid  them  cannot  be 
doubted.  Even  if  little  knowledge,  measured  by  some  stand- 
ards, can  be  acquired  in  six  or  eight  weeks,  the  stimulus  and 
inspiration  received  by  contact  with  some  master  of  the  subject 
may,  even  in  a  brief  time,  bring  forth  new  life  in  the  teacher  who 
was  dying  from  isolation,  and  give  new  vitality  to  his  whole 
thought  and  work. 

The  word  isolation  reminds  us  that  no  efforts  of  a  single  in- 
dividual can  ward  off  for  a  long  time  the  inevitable  petrifaction. 
Contact  with  other  people  with  like  interests  is  indispensable. 
For  this  reason  the  meetings  of  local  scientific  and  educational 
societies,  and  the  conventions  of  the  American  Association 
for  the  Advancement  of  Science  and  the  American  Chemical 


1  For  the  encouragement  of  this  work  amongst  its  teachers,  the  Board 
of  Education  of  Chicago  pays  the  expenses  of  any  investigations  they 
may  make,  provided  the  results  on  whose  accomplishment  the  claims  are 
based  are  certified  by  some  competent  authority  to  be  genuine  additions 
to  knowledge.  This  most  enlightened  policy  might  be  with  advantage 
imitated  by  other  school  authorities  in  the  country. 


2l8  THE    TEACHER 

Society  furnish  opportunities  of  receiving  help  which  should 
not  be  missed.  Visiting  other  schools  and  watching  the  work 
of  other  teachers  should  also  be  indulged  in  as  frequently  as 
possible. 

As  has  been  said  before,  the  teaching  of  beginning  chemistry 
is  the  most  difficult  task  which  the  chemist,  no  matter  what  his 
NoPrepara-  training,  can  undertake.  Teaching  it  in  a  secon- 

tion  too  Great  dary  school  is  more  difficult  than  teaching  it  in  a 
for  the  Task.  /  .  ,  .  ,.„  &,  , 

university,  and   incomparably  more    difficult   than 

giving  instruction  in  some  advanced  branch  of  the  subject,  or, 
assuming  proportionate  preparation  of  the  teacher,  even  super- 
vising the  work  of  students  engaged  in  research.  These  tasks 
are  all  different  and  require  perhaps  somewhat  different  quali- 
fications, but  the  delicate  operation  of  dealing  with  a  young 
pupil  who  is  beginning  the  study  of  a  science,  so  as  to  impart 
to  the  small  change  of  the  subject  the  ring  of  the  genuine 
metal  and  the  stamp  of  truth  and  authority,  requires  a  breadth 
and  at  the  same  time  a  minuteness  of  knowledge  which  only 
long  training  and  experience  can  give.  The  maturity  and 
resourcefulness  which  are  born  of  a  thorough  control  of  the 
subject  cannot  be  communicated.  They  are  the  fruit  of  un- 
remitting and  long  continued  labour. 

III.     Literature  for  the  Teacher. 

It  is  impossible  here  to  mention  all  even  of  the  important 
works  dealing  with  every  branch  of  chemistry.  In  the  following 
bibliography  the  titles  have  been  selected  in  the  main  with 
reference  to  the  needs  of  the  teacher.  There  are  included, 
however,  a  number  which  are  adapted  also  to  the  use  of  pupils. 
A  few  volumes  should  be  added  yearly  to  the  reference  shelf  in 
the  laboratory,  in  order  that  encouragement  to  excursions  out- 
side the  narrow  limits  of  the  regular  text-book  may  not  be 
wanting.  The  books  have  been  classified  and,  under  each 
head,  after  some  remarks  in  regard  to  sources  of  information 
on  the  particular  branch  of  the  subject,  the  bibliographical 
description  of  commendable  works  is  given.  In  the  case  of 


THE    TEACHER  2 19 

many  topics  the  appropriate  references  have  appeared  already 
in  earlier  chapters.1 

Dictionaries ,  etc :  — Watts'  Dictionary  contains  articles  varying 
in  length  from  a  few  lines  to  many  pages  on  every  chemical  sub- 
stance and  every  topic  in  scientific  chemistry.  Technological 
subjects  have  been  relegated  to  Thorpe's  Dictionary.  Exten- 
sive tables  including  much  indispensable  information  will  be 
found  in  the  Chemiker  Kalendar  and  Meade's  Pocket  Manual. 
The  articles  in  the  Encyclopedia  Britannica  and  other  works 
of  the  same  class  frequently  treat  subjects  hardly  noticed  in  text- 
books. In  using  them  due  regard  must  be  paid  to  the  time  at 
which  the  articles  were  written. 

Watts.  Dictionary  of  Chemistry.  Edited  by  Morley  and  Muir. 
4  vols.,  half  leather.  London  and  New  York,  Longmans,  Green  &  Co. 
1894. 

Thorpe,  T.  E.  Dictionary  of  Applied  Chemistry.  3  vols.,  half  leather. 
London  and  New  York,  Longmans,  Green  &  Co.  1894-95. 

Biedermann.     Chemiker  Kalendar.     Berlin,  Springer.     Annually. 

Meade.  The  Chemists'  Pocket  Manual.  Easton,  Pa.,  Chemical  Pub. 
Co.  1900. 

Inorganic  Chemistry,  Larger  Works :  —  The  most  useful,  ex- 
tensive work  of  reference  is  the  inorganic  portion  of  Roscoe 
and  Schorlemmer's  Treatise.  It  has  recently  been  brought  up 
to  date.  The  other  works,  which  may  be  classed  as  university 
text-books,  have  each  well-defined  merits  of  their  own.  Rem- 
sen  is  notable  for  lucidity ;  Newth,  for  attention  to  industries ; 
Freer,  for  the  treatment  of  certain  chapters  ;  Richter,  for  the 
remarkable  amount  of  information  it  gives  for  its  size  ;  Ramsay, 
for  the  arrangement  of  the  material.  Ostwald's  Outlines  is  an 
attempt  to  apply  the  latest  developments  of  physical  chemistry 
to  inorganic  chemistry,  and  is  highly  suggestive.  The  small 


1  The  reader  is  referred  for  references  on  the  following  topics  to  the 
appropriate  parts  of  this  book  :  Elementary  text-books  on  inorganic  chem- 
istry, pp.  55-60;  Laboratory  manuals,  pp.  104,  113,  115-119,  192,  216; 
Questions  and  problems,  pp.  133,  136;  Inorganic  preparations,  p.  211  ; 
Lecture  experiments,  pp.  134,  167,  169,  170  ;  Glassworking  and  technique, 
p.  113.  Fundamental  conceptions  of  the  scientific  method,  pp.  147-153. 


220  THE    TEACHER 

Modern  Chemistry  of  Ramsay  is  a  highly  successful  attempt  to 
give  a  bird's-eye  view  of  the  same  aspect  of  the  subject.  The 
teacher  should  have  as  many  of  these  books  as  possible  at  his 
command. 

Roscoe  and  Schorlemmer.  Treatise  on  Chemistry.  Vols.  I.  and  II., 
Inorganic.  London,  Macmillan.  New  York,  D.  Appleton  &  Co.  1898. 

Mendeleeff-Greenaway.  Principles  of  Chemistry.  2  vols.  London 
and  New  York,  Longmans,  Green  &  Co.  1897. 

E-emsen.  Chemistry,  Advanced  Course.  New  York,  Henry  Holt 
&  Co.  London,  Macmillan.  1898. 

Newth.  Text-Book  of  Inorganic  Chemistry.  London  and  New  York, 
Longmans,  Green  &  Co.  1897. 

Freer.     General  Inorganic  Chemistry.    Boston,  Allyn  &  Bacon.    1894. 

Richter-Smith.  Inorganic  Chemistry.  Philadelphia,  Blakiston. 
London,  Kegan  Paul,  Trench  &  Co.  1900. 

Ramsay.  A  System  of  Inorganic  Chemistry.  London,  Churchill. 
1891. 

Bloxam.  Inorganic  and  Organic  Chemistry.  London,  Churchill. 
Philadelphia,  Blakiston.  1901. 

Ostwald-Findlay.  Principles  of  Inorganic  Chemistry.  London  and 
New  York,  Macmillan.  1902. 

Ramsay.  Modern  Chemistry.  Part  I.,  Theoretical ;  Part  II.,  Syste- 
matic. London,  J.  M.  Uent.  New  York,  Macmillan.  1901. 

Theoretical:  —  Walker's  Physical  Chemistryis  generally  held 
to  give  the  clearest  account  of  the  subject  which  has  so  far 
appeared.  Lehfeldt's  is  less  well  known.  It  is  wonderfully 
comprehensive  for  its  size,  and  well  balanced  in  the  relative 
space  given  to  different  topics.  Dobbin  and  Walker  is  ele- 
mentary. The  teacher  is  advised  to  study  several  works  on  this 
subject,  including  some  on  special  parts  of  the  subject  like  those 
appended  to  the  list,  as  it  is  in  this  way  only  that  a  clear  under- 
standing of  the  theory  can  be  obtained.  The  second  and  third 
last  books  are  reprints  of  original  papers,  and  the  last  contains 
a  description  of  some  laboratory  methods. 

"Walker.  Introduction  to  Physical  Chemistry.  London  and  New 
York,  Macmillan.  1899. 

Lehfeldt.  Text-Book  of  Physical  Chemistry.  London,  Edward 
Arnold.  New  York,  Longmans,  Green  &  Co.  1899. 

Nernst-Palmer.  Theoretical  Chemistry.  New  York  and  London, 
Macmillan.  1895. 


THE    TEACHER  221 

Dobbin  and  Walker.  Chemical  Theory  for  Beginners.  London  and 
New  York,  Macmillan.  1892. 

Morgan.  Elements  of  Physical  Chemistry.  New  York,  John  Wiley 
&  Sons.  1899. 

Jones.  The  Elements  of  Physical  Chemistry.  New  York  and 
London,  Macmillan.  1902. 

Jones.  The  Theory  of  Electrolytic  Dissociation.  New  York  and 
London,  Macmillan.  1900. 

Ostwald-Muir.  Solutions.  London  and  New  York,  Longmans, 
Green  &  Co.  1891. 

Le  Blanc- Whitney.  Elements  of  Electro-Chemistry.  New  York 
and  London,  Macmillan.  1896. 

Liipke-Muir.  Elements  of  Electro-Chemistry.  London,  Grevel  & 
Co.  Philadelphia,  Lippincott.  1897. 

PfefTer-Van  't  Hoff-Arrhenius-Raoult-Jones.  The  Modern  Theory 
of  Solution.  New  York,  American  Book  Co.  1899. 

Faraday-Hittorf-Kohlrausch-Goodwin.  Fundamental  Laws  of  Elec- 
trolytic Conduction.  New  York,  American  Book  Co.  1899. 

Jones.  The  Freezing  Point,  Boiling  Point,  and  Conductivity  Methods. 
Easton,  Pa.,  Chemical  Pub.  Co.  1897. 

Of  an  entirely  different  character  are  the  three  following 
books.  They  do  not  profess  to  give  much  or,  in  the  cases  of 
the  two  last,  any  attention  to  the  theory  of  solutions.  They 
discuss  the  atomic  theory,  the  constitution  of  chemical  sub- 
stances, the  periodic  law,  and  other  subjects,  with  a  strong 
infusion  of  the  historical  method  in  their  mode  of  treating  them. 
They  will  be  found  exceedingly  valuable. 

Tilden.  Introduction  to  the  Study  of  Chemical  Philosophy.  London 
and  New  York,  Longmans,  Green  &  Co.  1902. 

Kemsen.  Principles  of  Theoretical  Chemistry.  Philadelphia,  Lea 
Bros.  &  Co.  London,  Bailliere,  Tindall  &  Cox.  1892. 

Lothar  Meyer.  Outlines  of  Theoretical  Chemistry.  London  and 
New  York,  Longmans,  Green  &  Co.  1899. 

Historical:  —  The  works  named  below  divide  themselves  into 
four  sets  :  the  general  treatises  on  the  history  of  the  science, 
histories  of  special  periods  or  special  parts  of  the  science,  bio- 
graphical works,  and  reprints  of  memoirs  of  historical  interest. 
Of  the  books  in  the  second  set,  Ramay's  Gases  of  the  Atmos- 
phere is  a  useful  supplement  to  the  treatment  of  the  air,  and 
particularly  of  oxygen,  as  it  is  found  in  the  text-books.  Car- 
negie treats  some  selected  topics  in  a  very  suggestive  manner. 


222  THE    TEACHER 

The  Alembic  Club  Reprints,  the  last  set,  supply  some  papers 
of  historical  interest  in  a  neat  and  inexpensive  form.  Study  of 
these  documents  gives  a  vivid  impression  of  the  attitude  and 
methods  of  the  early  workers  which  cannot  be  obtained  except- 
ing by  reading  their  own  descriptions  of  their  labours. 

Tilden.  A  Short  History  of  the  Progress  of  Scientific  Chemistry 
in  Our  Own  Times.  London  and  New  York,  Longmans,  Green  &  Co. 
1899. 

von  Meyer-McGowan.  History  of  Chemistry.  London  and  New 
York,  Macmillan.  1891. 

Ladenburg-Dobbin.  Lectures  on  the  History  of  the  Development 
of  Chemistry  Since  the  Time  of  Lavoisier.  Edinburgh,  The  Alembic 
Club,  Wm.  F.  Clay  (Agent).  1900. 

Venabie.  A  Short  History  of  Chemistry.  Boston,  D.  C.  Heath  &  Co. 
1894. 

Muir.  The  Alchemical  Essence  and  the  Chemical  Element.  London 
and  New  York,  Longmans,  Green  &  Co.  1894. 

Kodwell.  The  Birth  of  Chemistry.  London  and  New  York,  Mac- 
millan. 1874. 

Thorpe.  Chemistry  in  Britain  in  the  XIX.  Century.  London,  JOUR- 
NAL OF  THE  CHEMICAL  SOCIETY,  LXXVII.  (1900),  562. 

Ramsay.  The  Gases  of  the  Atmosphere.  London  and  New  York, 
Macmillan.  1896. 

Carnegie.  Law  and  Theory  in  Chemistry.  London  and  New  York, 
Longmans,  Green  &  Co.  1894. 

"Wurtz.  The  Atomic  Theory.  London,  Kegan  Paul,  Trench  &  Co. 
New  York,  D.  Appleton  &  Co,  '1891. 

Venabie.  The  Development  of  the  Periodic  Law.  Easton,  Pa., 
Chemical  Pub.  Co.  1898. 

Thorpe.  Essays  in  Historical  Chemistry.  London  and  New  York, 
Macmillan.  1894. 

Tyndall.  Faraday  as  a  Discoverer.  London,  Longmans,  Green  &  Co. 
New  York,  D.  Appleton  &  Co.  1894. 

Muir.  Heroes  of  Science,  —  Chemists.  London,  S.  P.  C.  K.  New 
York,  E.  and  J.  B.  Young  &  Co.  1883. 

Thorpe.  Humphrey  Davy.  Century  Science  Series.  London  and 
New  York,  Macmillan.  1896. 

Roscoe.  John  Dalton.  Century  Science  Scries.  London  and  New 
York,  Macmillan.  1895. 

Thompson.  Michael  Faraday.  Century  Science  Series.  London  and 
New  York,  Macmillan.  1899. 

Shenstone.  Justus  von  Liebig.  Century  Science  Series.  London 
and  New  York,  Macmillan.  1895. 


THE    TEACHER  22$ 

Mallett.  Memorial  Lecture  on  Stas.  London,  JOUR.  CHEM.  Soc., 
LXIII.  (1893),  l  >  JOUR.  AM.  CHEM.  Soc.,  Sept.  1892. 

Playfair-Abel-Perkms-Armstrong.  Memorial  Addresses  on  Hof- 
maun.  London,  JOUR.  CHEM.  Soc.,  LXIX.  (1896),  575-732. 

Japp.  Memorial  Lecture  on  Kekule.  London,  JOUR.  CHEM.  Soc., 
LXXIII.  (1898),  97. 

Roscoe.  Memorial  Lecture  on  Bunsen.  London,  JOUR.  CHEM.  Soc., 
LXXVII.  (1900),  513. 

Chemical  Society  of  London.  Twelve  Memorial  Addresses  (col- 
lected). London,  Gurney  &  Jackson.  1901. 


Alembic  Club  Keprints.  Edinburgh,  Wm.  F.  Clay  (Agent).  Easton, 
Pa.,  Chemical  Pub.  Co. 

1.  Black.     Experiments  upon  Magnesia  Alba,  etc. 

2.  Dalton,  Wollaston,  and  Thomson.     Foundations  of  the  Atomic 
Theory. 

3.  Cavendish.     Experiments  on  Air. 

4.  Dalton,  Gay-Lussac,  and  Avogadro.    Foundations  of  the  Molec- 
ular Theory. 

5.  Hooke.     Extracts  from  Micrographia. 

6.  Davy.      The    Decomposition    of     the    Alkalies    and    Alkaline 
Earths. 

7.  Priestley.     The  Discovery  of  Oxygen. 

8.  Scheele.     The  Discovery  of  Oxygen. 

9.  Davy.     The  Elementary  Nature  of  Chlorine. 

10.  Graham.     Researches  on  the  Arseniates,  Phosphates,  and  Modifi- 
cations of  Phosphoric  Acid. 

11.  Jean  Rey.     On  an  Enquiry  into  the  Cause  Wherefore  Tin  and 
Lead  Increase  in  Weight  on  Calcination. 

12.  Faraday.     The  Liquefaction  of  Gases. 

13.  Scheele,  Berthollet,  Morveau,  Gay-Lussac,  and  Thenard.    The 
Early  History  of  Chlorine. 

14.  Pasteur.     Researches  on  the  Molecular  Asymmetry  of  Natural 
Organic  Products. 

1 5.  Kolbe.     Papers  on  the  Electrolysis  of  Organic  Compounds. 
Reprints  of  Science  Classics.     Chicago  :  The  School  Science  Press. 
No.  i.    Lavoisier.     The  Analysis  of  Air  and  Water.    Tr.  by  C.  E. 

Linebayer.     1902. 

Organic :  —  The  chemistry  of  the  carbon  compounds  is 
treated  most  comprehensively  in  the  new  edition  of  Richter's 
Organic  Chemistry.  Remsen's  work  gives  an  elementary  ac- 
count of  the  subject  and  describes  illustrative  experiments. 
Hjelt  gives  a  survey  of  the  generalizations  of  organic  chemistry. 

Ritcher-Smith.  Organic  Chemistry.  2  vols.  Philadelphia,  Blakis- 
ton.  London,  Kegan  Paul,  Trench  &  Co.  1900. 


224  THE    TEACHER 

Bemsen.  Introduction  to  the  Study  of  the  Compounds  of  Carbon. 
Boston,  D.  C.  Heath  &  Co.  London,  Macmillan.  1895. 

Perkin  and  Kipping.  Organic  Chemistry.  2  vols.  Edinburgh, 
Chambers.  Philadelphia,  Lippincott.  1894. 

Hjelt-Tingle.  Principles  of  General  Organic  Chemistry.  London  and 
New  York,  Longmans,  Green  &  Co.  1895. 

For  laboratory  work  in  organic  chemistry,  the  collections  of 
selected  preparations  by  Noyes  and  by  Gattermann  are  excellent. 
Of  a  more  elementary  character  are  Garrett  and  Harden,  Orn- 
dorrT,  and  Turpin.  A  compendium  of  all  organic  methods  of 
work,  with  copious  illustrations  of  their  application,  and  numer- 
ous references  to  the  original  literature,  will  be  found  in  Lassar- 
Cohn.  Noyes  and  Mulliken's  book  gives  a  different  and  highly 
instructive  view  of  the  subject. 

Noyes.  Organic  Chemistry  for  the  Laboratory.  Easton,  Pa.,  Chemi- 
cal Pub.  Co.  1897. 

Gattermann-Shober.  Practical  Methods  of  Organic  Chemistry. 
London  and  New  York,  Macmillan.  1901. 

Garrett  and  Harden.  Elementary  Course  of  Practical  Organic  Chem- 
istry. London  and  New  York,  Longmans,  Green  &  Co.  1897. 

Orndorff.  Laboratory  Manual  of  Organic  Chemistry.  Boston,  D.  C. 
Heath  &  Co.  1893. 

Lassar-Cohn-Smith.  Laboratory  Manual  of  Organic  Chemistry. 
London  and  New  York,  Macmillan.  1895. 

Noyes  and  Mulliken.  Laboratory  Experiments  on  the  Class-Reac- 
tions and  Identification  of  Organic  Substances.  Easton,  Pa.,  Chemical 
Pub.  Co. 

Industrial:  —  Thorp's  is  the  most  recent  work  on  the  sub- 
ject. It  includes  all  industries  excepting  the  metallurgical. 
Borchers'  work  gives  an  excellent  account  of  the  recent  appli- 
cations of  electricity  in  technological  chemistry. 

Thorp,  F.  H.  Outlines  of  Industrial  Chemistry.  London  and  New 
York,  Macmillan.  1899. 

Huntington  and  McMillan.  Metals.  London  and  New  York,  Long- 
mans, Green  &  Co.  1897. 

Borchers.  Electro-Smelting  and  Refining.  London,  C.  Griffin  &  Co- 
Philadelphia,  Lippincott.  1897. 

Wagner.  Manual  of  Chemical  Technology.  London,  Churchill. 
New  York,  D.  Appleton  &  Co.  1895. 


THE    TEACHER  22$ 

Analytical:  —  The  standard  works  of  reference  on  this  sub- 
ject are  those  of  Fresenius.  The  most  satisfactory  treatment  of 
both  branches  in  one  volume  is  represented  by  Newth's  book. 
Perkin's  work  gives  special  attention  to  organic  analysis.  Ost- 
wald's  Scientific  Foundation  is  indispensable,  whatever  other 
works  are  employed,  as  none  of  the  treatises  on  analysis  pay 
sufficient  attention  to  the  theory,  and  most  pay  no  attention  to 
it  whatever. 

Ostwald-McGowan.  Scientific  Foundations  of  Analytical  Chemistry. 
London  and  New  York,  Macmillan.  1900. 

Fresenius.  Manual  of  Qualitative  Analysis.  London,  Churchill.  New 
York,  John  Wiley  &  Sons.  1890. 

Fresenius.  Quantitative  Chemical  Analysis.  London,  Churchill. 
New  York,  John  Wiley  £  Sons.  1881. 

Newth.  Chemical  Analysis,  Qualitative  and  Quantitative.  London 
and  New  York,  Longmans,  Green  &  Co.  1898. 

Noyes,  W.  A.  Elements  of  Qualitative  Analysis.  New  York,  Henry 
Holt  &  Co.  1901. 

Perkin,  F.  M.  Qualitative  Chemical  Analysis.  London  and  New 
York,  Longmans,  Green  &  Co.  1901. 

Noyes,  A.  A.  Qualitative  Chemical  Analysis.  London  and  New 
York,  Macmillan.  1899. 

Clowes  and  Coleman.  Elementary  Quantitative  Chemical  Analysis. 
London  (4th  ed.  1897),  Churchill.  Philadelphia,  Blakiston. 

Sutton.  Handbook  of  Volumetric  Analysis.  London,  Churchill. 
Philadelphia,  Blakiston.  1890. 

Thornton  and  Pearson.  Notes  on  Volumetric  Analysis.  London 
and  New  York,  Longmans,  Green  &  Co.  1898. 

Hempel-Dennis.  Elements  of  Gas  Analysis.  London  and  New 
York.  Macmillan.  1891. 

Mason.  Examination  of  Water.  New  York,  John  Wiley  &  Sons. 
London,  Chapman  &  Hall.  1899. 

Blair.  The  Chemical  Analysis  of  Iron.  Philadelphia,  Lippincott. 
1902. 

Smith,  E.  P.  Electro-Chemical  Analysis.  Philadelphia,  Blakiston. 
1894. 

Classen.  Quantitative  Chemical  Analysis  by  Electrolysis.  New  York, 
John  Wiley  &  Sons  London,  Chapman  &  Hall.  1898. 

Landauer-Tingle.  Spectrum  Analysis.  New  York,  John  Wiley  & 
Sons.  London,  Chapman  &  Hall.  1898. 

Chemistry  of  Daily  Life : — Information  about  the  chemistry  of 
common  things  is  scattered  through  an  immense  range  of  litera- 
ture. Works  on  special  branches  of  analysis  and  on  special 


226  THE   TEACHER 

industries,  works  on  botany,  physiology,  etc.,  and  many  others 
can  contribute  much  to  a  knowledge  of  this.  The  following  pro- 
fess to  deal  with  such  matters  in  a  popular  way. 

Johnston.  Chemistry  of  Common  Life.  London,  Blackwood.  New 
York,  D.  Appleton  &  Co.  1879. 

Lassar-Cohn-Muir.  Chemistry  of  Daily  Life.  London,  Grevell  & 
Co.  Philadelphia,  Lippincott.  1898. 

Martin.  Story  of  a  Piece  of  Coal.  London,  Geo.  Newnes.  New 
York,  D.  Appleton  &  Co.  1896. 

Faraday.  Chemical  History  of  a  Candle.  London,  Chatto  &  Windus. 
New  York,  Harper  &  Brothers.  1862. 

"Williams.  The  Chemistry  of  Cooking.  London,  Chatto  &  Windus. 
New  York,  Appleton  &  Co.  1885. 

Richards  and  Elliott.  Chemistry  of  Cooking  and  Cleaning.  Boston, 
Home  Science  Pub.  Co.  1897. 

Richards.  Food  Material  and  their  Adulterations.  Boston,  Home 
Science  Pub.  Co.  1886. 

King.     The  Soil.     London  and  New  York,  Macmillan.     1899. 

Roberts.  The  Fertility  of  Land.  New  York  and  London,  Macmillan. 
1897. 

Miscellaneous  :  —  From  the  works  on  the  many  branches  of 
chemistry  which  have  not  been  treated  separately,  a  few  titles 
have  been  selected.  The  bibliography  of ^  the  New  England 
Association  of  Chemistry  Teachers,  to  which  I  am  indebted  for 
some  of  the  data  in  these  lists,  gives  a  brief  description  of  the 
nature  of  each  of  the  books  contained  in  it.  It  will  be  found 
very  useful. 

Williams.  Elements  of  Crystallography.  New  York,  Henry  Holt  & 
Co.  1892. 

Bauerman.  Descriptive  Mineralogy.  London  and  New  York,  Long- 
mans, Green  &  Co. 

Dana,  E.  S.  A  Text-Book  of  Mineralogy.  New  York,  John  Wiley 
&  Sons.  London,  Chapman  &  Hall.  1898. 

Abney.  Treatise  on  Photography.  London  and  New  York,  Long- 
mans, Green  &  Co.  1901. 

Meldola.  Chemistry  of  Photography.  London  and  New  York,  Mac- 
millan. 1889. 

Halliburton.  Essentials  of  Chemical  Physiology.  London  and  New 
York,  Longmans,  Green  &  Co.  1901. 

Hueppe- Jordan.  Principles  of  Bacteriology.  Chicago,  Open  Court 
Pub.  Co.  London,  Kegan  Paul,  Trench  &  Co.  1899. 


THE   TEACHER 

Frankland.  Our  Secret  Friends  and  Foes.  London,  S.  P.  C.  K. 
New  York,  E.  &  J.  B.  Young  &  Co.  1897. 

Schiirtzenbreger.  On  Fermentation.  London,  Kegan  Paul,  Trench 
&  Co.  New  York,  D.  Appleton  &  Co.  1889. 

New  England  Association  of  Chemistry  Teachers.  List  of  Books  in 
Chemistry.  Boston,  L.  E.  Knott  Apparatus  Co.  1900. 

Periodicals  :  —  The  best  way  to  keep  in  touch  with  chemical 
work  is  to  read  at  least  one  journal  regularly.  The  first  five  on 
the  list  publish  original  articles.  In  addition  to  this,  the  second 
contains  reviews  of  all  the  chemical  research  done  in  America. 
The  third  contains  reviews  of  all  chemical  memoirs,  wherever 
published.  The  fourth  is  admirably  edited,  and  furnishes 
excellent  abstracts  of  a  large  amount  of  work,  even  when  it 
is  mainly  of  scientific  interest  and  has  little  actual  bearing  on 
industry.  Numbers  six  to  eight  publish  articles  on  all  the 
sciences,  including  chemistry.  The  last  three  frequently  con- 
tain articles  dealing  with  the  teaching  of  chemistry. 

American  Chemical  Journal.  Baltimore,  Md.,  The  Johns  Hopkins 
University  Press.  Monthly. 

Journal  of  the  American  Chemical  Society.  Easton,  Pa.,  Chemical 
Pub.  Co.  Monthly. 

Journal  of  the  Chemical  Society.  London,  Gurney  &  Jackson. 
Monthly. 

Journal  of  the  Society  of  Chemical  Industry.  London,  Eyre  & 
Spottiswoode.  Monthly. 

Chemical  News.     London,  E.  J.  Davey.     Weekly. 

Science.     New  York,  Macmillan.     Weekly. 

Nature.     London  and  New  York,  Macmillan.     Weekly. 

Popular  Science  Monthly.     New  York,  McClure,  Phillips  &  Co. 

School  Science.     Chicago,  138  Washington  Street.     Monthly. 

School  Review.    Chicago,  The  University  of  Chicago  Press.  Monthly. 

Zeitschrift  fur  den  physikalischen  und  chemischen  Unterricht. 
Berlin. 


THE    TEACHING    OF    PHYSICS    IN 
THE   SECONDARY   SCHOOL 

BY  EDWIN    H.    HALL,  PH.D. 
PROFESSOR  OF  PHYSICS  IN  HARVARD  UNIVERSITY. 


Prefatory  Note 


IN  writing  the  first  four  chapters  on  the  teaching  of  physics 
the  author  has  had  in  mind  especially  the  school-teacher,  from 
the  time  when,  perhaps  only  a  boy,  he  is  making  choice  of  a 
profession  to  the  time  of  his  full  career  in  charge  of  a  well 
appointed  school  laboratory  and  class  room.  The  motives 
and  considerations  which  should  influence  the  choice  of  this 
career,  the  academic  and  other  preparation  which  the  prospec- 
tive teacher  should  make  for  it,  the  means  by  which  he  may 
keep  himself  in  continual  progress  as  a  teacher,  and  the  kind 
of  practical  problem  in  which  he,  without  undertaking  what  is 
commonly  called  original  research,  may  find  profitable  em- 
ployment for  any  amount  of  energy  in  the  improvement  of  his 
work,  are  all  touched  upon  in  these  four  chapters. 

In  the  next  chapter  the  change  of  aim  and  method  in  school 
physics  teaching  during  the  past  twenty  years  is  briefly  dis- 
cussed in  connection  with  changes  in  text-books.  This  leads 
naturally  to  a  consideration,  in  Chapter  VI.,  of  the  proper 
general  spirit  and  method  of  laboratory  instruction  in  schools. 
The  next  two  chapters  deal,  respectively,  with  technicalities  of 
laboratory  management,  and  with  the  very  important  functions 
of  lectures  and  recitations  in  connection  with  laboratory  work. 

In  Chapter  IX.  the  possibilities  of  physics  teaching  in  pri- 
mary and  grammar  schools  are  taken  up.  In  the  next  chapter 
attention  is  given  to  physics  in  secondary  schools,  and  the 
question  is  raised  whether,  after  all,  in  view  of  their  probable 
difference  in  scholarly  quality,  the  boy  who  is  going  to  college 
and  the  boy  who  is  not  going  to  college  should  follow  the 
same  course  of  physics  in  school,  or,  rather,  whether  the  dis- 


232  PREFATORY  NOTE 

tinctively  preparatory  school  on  the  one  hand  and  the  high 
school  on  the  other  hand  should  have  just  the  same  kind  of 
physics  teaching  and  work. 

Chapter  XL,  On  The  Presentation  of  Dynamics,  is  the  only 
chapter  in  the  book  which  is  devoted  to  any  one  part,  exclu- 
sively, of  physics,  the  exception  in  this  case  being  justified,  in 
the  opinion  of  the  author,  by  the  exceptional  difficulty  and 
importance  of  the  subject  of  dynamics. 

Chapter  XII.  gives  a  plan  of  rooms  and  fittings  for  a  school 
department  of  physics,  and  Chapter  XIII.,  the  last,  gives  some 
account  of  the  state  of  physics  teaching  in  the  schools  of 
Germany,  England,  and  France. 

The  book  assumes  throughout  that  the  system  of  physics 
instruction  by  combined  laboratory  and  class  room  w6fk  is 
now  permanently  established  for  the  better  class  of  American 
secondary  schools ;  and  the  author  believes  it  to  be  the  especial 
privilege  and  duty  of  American  teachers  of  physics  so  to 
develop  and  perfect  this  system  as  to  make  it  not  only  a  great 
benefit  and  advantage  to  ourselves,  but  a  model  for  imitation 
by  the  schools  of  Europe,  most  of  which,  on  the  Continent  at 
least,  have  hardly  ventured  as  yet  upon  the  experiment  which 
we  are  here  working  out  to  a  successful  conclusion. 

In  the  bibliography  which  is  distributed  among  these  chapters 
the  author  has  certainly  not  included  all  the  good  books,  and 
he  does  not  feel  sure  that  he  has  left  out  all  the  bad  ones. 
Comments  on  the  various  text-books  named  are  given  in  very 
few  cases,  the  fact  being  that,  according  to  the  autlp-'s  experi- 
ence, no  one  knows  thoroughly  the  possibilities  of  a  book  for 
good  or  evil  till  he  has  taken  a  class  through  it. 

Writing  these  chapters  has  interested  the  author  and  has 
improved  his  own  teaching.  He  hopes  that  reading  them  may 
be  equally  beneficial  to  others. 

EDWIN    H.   HALL. 

CAMBRIDGE,  MASS. 
March,  1902. 


The 

Teaching  of  Physics  in  the 
Secondary  School 

CHAPTER   I 

WHETHEK   TO   BE  A   TEACHER   OF   PHYSICS 
REFERENCES. 

Eliot,  C.  W.  What  Is  A  Liberal  Education  ?  The  Century,  June, 
1884.  Educational  Reform.  New  York,  The  Century  Co.  1898. 

Fitch,  Sir  Joshua.  Thomas  and  Matthew  Arnold,  Great  Educators 
Series.  London,  W.  Heinemann,  Charles  Scribner's  Sons.  1897.  Pp.  277. 

Hart,  A.  B.  The  Teacher  as  a  Professional  Expert.  SCHOOL  REVIEW, 
I.  4-14. 

Huxley,  T.  H.  Science  and  Education,  Vol.  III.  of  the  Essays.  Lon- 
don, Macmillan  &  Co.  New  York,  D.  Appleton  &  Co.  1894. 

Spencer,  Herbert.  Education.  London,  Williams  &  Norgate.  New 
York,  D.  Appleton  &  Co. 

\Velldon,  J.  E.  C.  The  Teacher's  Training  of  Himself.  Contempo- 
rary Review.  March,  1893.  PP-  369-386. 

As  in  every  other  department  of  pedagogic  art,  there  is  in 
physics  the  teacher  who  is  born  and  the  teacher  who  is  made. 
The  latter,  if  successful,  is  the  product  of  infinite  labour,  of  long- 
suffering  patience  with  himself,  of  constant  courage,  of  never- 
dying  willingness  to  learn ;  but  all  this  is  equally  true  of  any 
man  who  aspires  to  excellence  in  any  art  for  which  his  native 
talent  is  not  conspicuous.  By  all  means,  let  every  man  find 
the  thing  he  can  do  best,  and  then  do  it  at  his  best. 

Why  should  a  man  be  a  teacher  of  any  kind?  First,  the 
negative  reasons,  which  may  be  somewhat  as  follows  :  Purely 


234  WHETHER   TO  BE  A    TEACHER 

manual  or  clerical  work  is  too  limited  in  its  mental  scope  and  is 
paid  too  little.  The  practice  of  medicine  would  be  too  painful 
Why  be  a  or  to°  critically  responsible.  The  pulpit  requires 
Teacher?  one  to  tajk  when  one  may  have  nothing  to  say. 
The  bar  imposes  a  professional  and  mercenary  contentiousness 
for  which  one  may  lack  both  taste  and  talent.  Business  success 
is  too  doubtful,  or  is  obtainable  at  too  great  a  price. 

The  positive  reasons.  The  profession  of  teaching  is  safe,  it 
is  honourable  ;  it  is,  it  may  be,  pre-eminently,  absolutely,  honest. 
It  brings  contact  with  and  influence  on  young  minds  in  a  plastic 
and  growing  condition.  Viewed  with  regard  to  society  at  large, 
to  civilization,  to  government,  instruction  is  construction.  To 
use  the  phrase  of  President  Eliot,  the  profession  of  teaching 
gives  a  man  a  chance  to  "  build  himself  into  "  the  great  fabric 
of  the  most  beneficent  and  enduring  human  institutions. 

And  so  we  have  chosen  to  be  teachers.  But  what  shall  I 
teach?  Shall  it  be  one  of  the  ancient  languages?  The  chil- 
whatshaiii  dren  of  the  American  public  are  not  likely  to  suffer 
Teach  ?  from  too  much  Latin  or  Greek.  We,  perhaps  more 

than  any  people  of  Europe,  need  to  be  told  and  shown  that  it 
is  possible  to  go  too  fast  straight  ahead,  that  the  beautiful, 
the  true,  the  desirable,  may  be  'behind  us,  that  the  most  whole- 
some, rational,  happy  living  is  consistent  with,  nay,  requires,  a 
certain  leisureliness  of  mind  which  takes  occasion  to  learn  how 
men  have  lived,  and  what  they  have  done  that  is  worth  remem- 
bering and  imitating.  On  these  or  similar  grounds  one  may 
amply  justify  the  choice  of  any  great  language,  or  literature,  or 
history,  as  the  sphere  of  his  life-work  as  a  teacher,  provided  he 
be  not  incompetent  for  the  task  to  which  he  devotes  himself. 

Why  then  should  we  turn  from  the  "  humanities,"  from  the 
study,  in  its  various  phases  and  achievements,  of  "  this  pleasing 
anxious  being,"  human  life,  to  experimental  and  mathematical 
science,  for  which  so  few  have  any  further  interest  than  a  desire 
to  enjoy  its  material  benefits  and  to  be  entertained  by  its  occa- 
sional spectacular  displays.  Putting  aside  for  the  moment  the 
question  of  individual  and  special  talents,  we  can  see  that  phys- 


WHETHER    TO  BE  A    TEACHER  235 

ical  science  has  for  some  minds,  or  some  temperaments,  a 
peculiar  charm  in  this,  that  it  holds  out  to  every  devotee  the 
possibility  of  making  by  himself  some  positive,  absolutely  new, 
addition  to  the  sum  total  of  permanent  useful  knowledge,  the 
certainty  of  moving  forward  into  regions  of  thought  and  of 
power  which  no  previous  generation  of  men  has  ever  pene- 
trated since  the  world  began.  This  motive  appeals  to  the 
north-pole  spirit,  of  which  every  true  follower  of  science  must 
have  a  dash,  the  spirit  which  can  find  pleasure  in  places  where 
the  air  is  cold  but  pure,  where  the  footing  is  rugged  but  forward. 
Contrasted  with  the  study  or  teaching  of  any  language,  as  such, 
the  study  and  teaching  of  science  offers,  as  the  object  of  espe- 
cial attention,  substance  instead  of  form ;  and  though  the  form 
in  the  one  case  be  the  expression  of  human  thought,  while  the 
substance  in  the  other  case  is  that  of  things  not  made  by  man, 
yet  we  who  are  of  the  school  of  science  cannot  admit,  because 
we  do  not  feel,  that  we  are  on  lower  ground.  He  only  should 
make  such  a  confession  who  follows  science  for  its  mere 
utilities. 

But,  given  the  intellectual  predisposition  in  favour  of  science, 
what  special  tastes  or  talents  should  prompt  or  justify  the 
choice  of  physics? 

The  most  desirable  qualities  are,  in  my  opinion  :  First,  capac- 
ity for  clear,  sustained,  correct  thinking,  most  conveniently 
tested  by  capacity  for  some  common  branch  of 
mathematics.  It  is  true  that  Faraday,  who  was  a  neededfor 
very  great  scientific  thinker  and  discoverer,  de- 
clared,  after  turning  the  handle  of  a  calculating  ma- 
chine, that  he  had  now  for  the  first  time  in  his  life  performed  a 
mathematical  operation.  It  is  true  that  Edison,  who  is  a  great 
scientific  man  of  a  different  kind,  has  said  that  he  never  could  do 
much  with  algebra,  being  bothered  by  the  plus  and  minus  signs. 
But  it  is  not  to  be  supposed  that  either  of  these  men  was  really 
lacking  in  mathematical  faculty.  The  fact  is  that  neither  of  them 
had,  as  a  boy,  much  regular  education.  Each  of  them  was 
carried  by  native  talent  early  in  life  into  conspicuous  achieve- 


236  WHETHER   TO  BE  A    TEACHER 

ments  in  science,  and  after  that  each  probably  felt,  consciously 
or  unconsciously  but  in  either  case  rightly,  that  to  go  back  and 
try  to  educate  himself  as  others  are  educated,  would  be  to  throw 
himself  off  the  track  of  already  assured  success. 

Moreover,  even  if  we  admit  that  mathematical  ability  is  not 
absolutely  essential  to  success  as  a  teacher  or  investigator  in 
physics,  we  must  find  that  the  literature  of  physics,  as  shown 
in  text-books  and  in  periodicals,  is  so  permeated  with  the  ideas 
and  the  symbols  of  mathematics,  that  a  person  who  at  the  out- 
set must  confess  to  a  weakness  with  respect  to  such  ideas  and 
symbols  would  enter  the  advanced  study  of  this  literature  under 
a  heavy  handicap. 

The  question  remains  whether  it  is  indispensable  that  the 
prospective  school-teacher  of  physics  shall  look  forward  to  what 
would  be  called,  among  physicists,  advanced  study.  This  ques- 
tion may  be  frankly  answered  in  the  negative.  One  can  get 
enough  of  physics  without  knowing  anything  of  the  calculus  to 
be  a  good  school-teacher  of  this  science.  No  energetic  man 
who  wishes  to  be  such  a  teacher  need  be  deterred  by  lack  of 
interest  in  mathematics,  provided  he  has  the  endowment,  which 
I  put  second,  with  some  doubt  whether  it  should  not  be  put 
first,  of  capacity  for  a  quick  understanding  of  machinery.  This 
may  show  itself  in  achievements  ranging  from  the  easy  mastery 
of  a  mouse-trap  to  the  easy  mastery  of  a  compound  steam- 
engine.  I  dwell  upon  facility  here,  for  the  reason  that  with 
facility  goes  liking,  and  with  liking  goes  knowledge,  and  a  wide 
acquaintance  with  machinery  and  apparatus  is  useful,  not  only 
in  equipping  and  maintaining  a  laboratory,  but  also  in  awaken- 
ing the  interest  and  holding  the  attention  of  pupils,  who,  whether 
mechanically  competent  or  otherwise,  always  admire  mechanical 
proficiency  in  others.  The  man  who  is  slow  to  think  out  the 
relations  and  working  of  a  machine  may  in  time  acquire  a  com- 
petent knowledge  of  such  apparatus  and  machinery  as  comes 
within  his  range  of  habitual  vision,  but  he  is  sure  to  have  an 
occasional  bad  five  minutes  in  the  presence  of  his  class  during 
the  early  years  of  his  teaching. 


WHETHER    TO  BE  A    TEACHER  237 

I  assume,  although  this  is  not  always  true,  that  a  considerable 
degree  of  manual  skill  and  proficiency  in  the  use  of  tools  will 
accompany  the  instinct  for  machinery. 

No  other  qualities  than  the  two  now  briefly  discussed  need 
be  mentioned  as  important  for  physics  especially,  though  of 
course  all  the  intellectual  virtues  count  here,  as  they  do  in 
other  teaching.  A  great  memory  for  facts  in  detail,  such  as 
the  chemist  needs,  the  habit  of  minute  general  observation,  so 
nearly  indispensable  to  the  naturalist,  —  these  traits  are  certainly 
useful  to  the  physicist,  but  he  can  do  without  them.  Inventive- 
ness, constructive  imagination,  is  eminently  desirable ;  but  a 
reasonable  measure  of  it  is  pretty  sure  to  be  associated  with 
the  mechanical  faculty  already  spoken  of,  and  an  unreasonable 
measure  of  it,  which  we  sometimes  find,  makes  its  possessor 
troublesome,  because  he  will  not  be  content  to  do  anything  as 
other  people  do  it,  but  must  invent  his  own  methods  for  every 
operation,  out  of  a  mere  wantonness  of  originality.  Necessity 
is  not  the  only  mother  of  inventions. 


CHAPTER    II 
PREPARATION   FOR   TEACHING 

REFERENCES. 

Barnett,  P.  A.  Common  Sense  in  Education  and  Teaching.  London 
and  New  York,  Longmans,  Green  &  Co.  1899.  Pp.  321. 

Cajori,  Florian.  A  History  of  Physics.  London  and  New  York, 
Macmillan.  1899.  Pp.  322. 

Lodge,  O.  J.  Pioneers  of  Science.  London  and  New  York,  Mac- 
millan. 1893.  Pp.  404. 

Monroe,  Will  S.  Bibliography  of  Education,  International  Educa- 
tional Series.  New  York,  D.  Appleton  &  Co. 

Munroe,  James  P.  The  Educational  Ideal.  Boston,  Heath  &  Co. 
1895.  IDP-  2^2- 

Osborn.  From  the  Greeks  to  Darwin.  London  and  New  York, 
Macmillan.  1896.  Pp.  259. 

Venable,  W.  H.  Let  Him  First  Be  a  Man.  Boston,  Lee  and  Shepard, 
Pp.  274. 

The  "Scientific  Memoirs  "  issued  by  the  American  Book  Company 
(New  York),  under  the  general  editorship  of  Professor  J.  S.  Ames,  are 
historically  interesting  and  valuable.  They  are  reprints  of  the  original 
papers  announcing  great  discoveries  or  important  general  laws,  and  are 
accompanied  by  biographical  sketches  of  the  authors. 

THE  first  thing  to  be  considered  under  this  heading  is  how 
to  get  a  competent  knowledge  of  the  subject-matter  and  the 
Knowledge  of  methods  of  the  science.  This  cannot  be  done  with- 
the  Subject.  out  much  text-book  study  and  much  laboratory  ex- 
perience. The  best  arrangement  of  work  combines  these  two 
methods  of  training,  from  the  school  days  on  to  the  attainment 
of  the  final  degree,  and  even  through  all  of  one's  professional 
life  ;  for  the  two  relieve  and  supplement  each  other,  and  the  time 
never  comes  when  the  aspiring  teacher  can  say,  I  know  enough 
for  my  work,  I  will  be  a  student  no  more,  or  when  he  can,  to 
the  best  advantage,  learn  by  print  alone. 


PREPARATION  FOR    TEACHING  239 

But  there  is  no   one   necessary  arrangement  and  order  of 
preparation  in  science.     The  young  man  whose  undergraduate 
days  are  spent  in  a  small  college,  where  the  oppor-   (Mer  and 
tunities  for  laboratory  work  may  be  very  limited,   Extent  of 
should  make   the  most  of  his  general  course   in 
physics,  which  will  probably  give  him  the  reading  of  a  good 
text-book,  and  the  seeing  of  a  greater  or  less  number  of  instruc- 
tive lecture-table   experiments,  should  attend  faithfully  to  his 
mathematics,  carrying  this  study  as  far  as   circumstances  will 
permit,  and  should  get  what  he  can  of  chemistry.     If  he  has 
done  all  this,  though  he  may  not  yet  be  a  specialist  in  physics, 
he  will  be  in  excellent  condition  to  appreciate  and  to  profit  by 
the  opportunities  which  he  should  seek  later  in  the  graduate 
school  of  some  university. 

But  how  long  should  the  period  of  formal  study  last,  how  far 
should  it  carry  the  prospective  teacher  before  he  begins  the 
practice  of  his  profession?  How  much,  for  example,  of  mathe- 
matics is  necessary?  Must  one  take  the  calculus?  Without 
unduly  magnifying  the  importance  and  solemnity  of  our  profes- 
sion, without  imitating  the  ambitious  example  of  those  who 
introduce  the  study  of  psychology  into  the  curriculum  of  a  cook- 
ing-school, we  are  compelled  to  pause  before  answering  these 
questions,  and  frame  some  brief  philosophy  of  the  objects  of 
education  and  of  the  functions  of  the  teacher. 

The  objects  of  education  in  science  are,  on  the  one  hand, 
to  make  men  capable,  self-sustaining,  physically  comfortable, 
on  the  other  hand,  to  increase  their  capacity  and   Objectsof 
opportunities  for  intellectual   enjoyment.      Each  of  Education  in 
these  objects  has  an  ethical  aspect ;  for  men  who   S 
are  materially  well-to-do,  and   intellectually  happy,  can  hardly 
help  being  good  men  and  good  citizens. 

If  all  communities  were  alike,  and  all  youths  in  each  commu- 
nity alike,  if  all  text-book  makers  wrote  with  perfect  apprecia- 
tion of  and  care  for  the  needs  of  these  young  people,  providing 
information,  training,  stimulus,  in  due  proportion  and  quantity, 
if  all  school  boards  made  ample  provision  for  the  use  of  such 


240  PREPARATION  FOR   TEACHING 

books,  —  if  all  these  conditions  held,  any  one  who  had  learned 
the  text-book  and  the  apparatus  described  by  it,  could  be  a 
successful  teacher,  and  the  profession  of  teaching  would  be 
honoured  and  paid  accordingly.  But  no  one  of  the  condi- 
tions mentioned  does  hold.  Communities  and  schools  in 
America  range  from  large  to  small,  from  rich  to  poor,  through 
many  fold,  from  rural  to  metropolitan,  from  the  racially  homo- 
geneous to  the  polyglot,  from  those  having  traditions  of  schol- 
arship to  those  having  no  traditions  at  all.  As  to  the  individual 
members  of  any  class  in  school,  some  have  capabilities  for  the 
theoretical  side  of  physics,  some  for  the  practical  side,  some 
for  neither.  School  boards  and  school  principals  may  be 
incapable  of  making  a  wise  choice  of  text-books,  which  vary 
greatly,  not  simply  from  good  to  bad  but  in  method  and 
purpose. 

Accordingly,  the  competent  teacher  is  not  a  mere  piece  of 
machinery,  made,  like  an  elevator,  to  run  with  safety  and  des- 
The  Teacher  Patcn>  carrying  its  load  of  passengers  through  a 
must  be  a  certain  fixed  distance  along  fixed  lines  and  then 
discharging  them,  without  responsibility  or  care  for 
their  future  fate  and  their  ultimate  destination.  He  is,  or  is 
prepared  to  be,  a  guide,  an  adviser.  However  narrow  his  habit- 
ual horizon,  he  must  know  what  lies  beyond  it.  He  must  ask, 
What  is  the  best  kind  of  training,  the  best  kind  of  information, 
the  best  kind  of  stimulus,  for  this  particular  class,  for  these  par- 
ticular individuals,  before  me?  How  can  I  make  this  year  they 
spend  with  me  count  most  toward  their  life-long  efficiency  and 
happiness  ?  How  can  I  best  develop  their  capabilities,  correct 
their  worst  tendencies,  influence  their  careers  ?  Of  course  every 
teacher  who  attempts  all  this  will  fail  -in  much  of  his  endeavour ; 
but  it  is  better  that  he  should  try,  and  that  he  should  make  in 
his  student  days  a  preparation  adequate  to  the  responsibility 
which  will  rest  upon  him.  v  This  means  that  he  must  know  well 
all  that  he  will  be  called  upon  to  teach  directly,  and  have  a 
good  general  knowledge  of  much  more.  He  may  not  be, 
probably  will  not  be,  in  active  teaching,  able  to  keep  up  his 


PREPARATION  FOR    TEACHING  241 

more  advanced  studies,  if  they  have  ever  extended  far ;  but  he 
will,  if  he  has  done  his  work  faithfully  and  intelligently,  retain 
at  least  an  enduring  reminiscence,  a  sustaining  memory,  that 
will  be  a  source  of  strength  to  himself  and  of  inspiration  to 
his  pupils. 

I  am  not  prepared,  as  some  others  may  be,  to  advise  that 
every  prospective  school-teacher  of  physics  should  take  the 
degree  of  Doctor  of  Philosophy ;  for  this,  requiring 
ordinarily  three  or  four  years  of  study  beyond  the 
baccalaureate  course,  a  high  degree  of  specialization,  and  much 
labour  devoted  to  research,  is  a  luxury,  a  superfluity  of  prepara- 
tion for  his  work,  which  the  school-teacher  cannot  usually  afford. 
The  degree  of  Master  of  Arts,  with  the  meaning  it  is  now  com- 
ing to  have,  as  the  certificate  of  one  or  two  years  of  graduate 
study,  usually  devoted  to  some  specialty,  but  with  little  or  no 
original  research,  seems  to  me  the  reasonable  goal  of  the  school- 
teacher in  preparation  at  present. 

I  have  said  elsewhere  that  one  can  be  a  good  school-teacher 
of  physics  who  knows  no  more  of  the  science  than  one  can  get 
without  the  calculus,  but  my  advice  to  the  teacher  Wee(i  Of 
who  wishes  to  realize  the  possibilities  of  his  pro-  Mathematics. 
fession  is  strongly  against  this  limitation.  Without  the  calculus 
one  can  read  almost  every  page  of  an  ordinary  general  English 
treatise  on  physics,  such  as  Barker,  Deschanel,  Ganot,  Hastings 
and  Beach,  Watson,  etc.,  all  of  Faraday's  writings,  Maxwell's 
Heat,  Tait's  Recent  Advances,  Lodge's  Modern  Views  of  Elec- 
tricity, and  a  great  deal  more  excellent  literature  of  physics. 
But  if  the  student  would  consult  the  larger  general  treatises,  or 
follow  the  progress  of  research  as  revealed  in  such  periodicals 
as  the  PHILOSOPHICAL  MAGAZINE  or  the  ANNALEN  DER  PHYSIK, 
he  will  find  himself  baffled  and  mortified,  if  he  has  not  a  good 
working  knowledge  of  this  mathematical  method  of  developing 
and  expressing  physical  theories.  It  is  true  that  a  good  deal  of 
what  is  thus  hidden  from  the  non-mathematical  reader  he  can 
perfectly  well  do  without.  It  is  also  true  that  one  who  has  a 
good  knowledge  of  the  calculus  is  likely  to  find  much  that  is 

16 


242  PREPARATION  FOR   TEACHING 

printed  very  hard  and  possibly  unprofitable  reading.  But 
he  who  has  become  familiar  with  the  language  of  the  calculus 
will  always  have  at  least  the  satisfaction  of  feeling  that  he 
has  the  key  to  the  gate  of  knowledge,  that  he  can  enter  the 
field  that  lies  before  him,  however  great  may  be  the  difficul- 
ties that  would  await  him  there.  This  sense  of  freedom,  of 
possibility,  is  worth  much,  even  though  it  may  be  rarely  put  to 
the  proof. 

In  the  training  of  the  teacher  of  physics  should  be  included 
a  respectable  amount  of  chemistry  as  well  as  of  mathematics, 
partly  because  the  chemistry  is  needed  in  connec- 
tion with  physics,  partly  because  the  teacher  of 
physics  is  likely  to  be,  at  first,  if  not  permanently,  a  teacher  of 
chemistry  also. 

One  "  course  "  of  study  being  counted  as  the  equivalent  of 
one  quarter  of  the  work  of  one  college  year,  the  Master  of 
Summary  of  Arts,  as  I  have  him  in  mind,  well  equipped  for  the 
Work.  school-teaching  of  physics  or  mathematics,  and 

tolerably  fitted  for  the  teaching  of  chemistry,  will  have  taken, 
in  addition  to  the  pre-college  physics  of  a  good  school,  about 
five  courses  in  physics,  two  or  more  courses  in  chemistry,  for 
the  character  of  which  the  reader  is  referred  to  Chapter  VIII. 
of  the  first  part  of  this  volume,  three  or  more  courses  in 
mathematics,  including  solid  geometry,  plane  trigonometry,  an- 
alytical geometry,  and  the  elements  of  calculus  with  applica- 
tions to  mechanics.  This  makes  ten  or  more  courses  of  science 
study,  the  equivalent  of  about  two  and  one-half  solid  years  of 
college  work,  out  of  the  whole  time,  at  least  five  years  and  often 
more,  supposed  to  pass  between  admission  to  college  and  the 
attainment  of  the  M.A.  degree. 

The  physics  may  well  include  one  course  or  somewhat  more 
in  a  general  text-book,  like  one  of  those  named  earlier  in  this 
M0re  chapter,  with  accompanying  laboratory  exercises  of 

Specific.  an  illustrative  and  not  too  exacting  character,  usually 
quantitative,  but  not  painfully  accurate,  a  course  of  careful  labo- 
ratory work,  with  much  text-book  study,  in  heat  and  light,  two 


PREPARATION  FOR    TEACHING  243 

such  courses  in  electricity  and  magnetism,  and  a  half  course  in 
thermodynamics.  Every  one  of  these  courses  except  the  first 
will  naturally  require  some  use  of  the  calculus. 

Somewhere  in  the  curriculum  the  student  should  learn  to 
take,  and  to  make  use  of,  the  indicator  diagram  of  a  steam- 
engine  and  the  characteristic  curves  of  dynamos. 
„      .         .  ,.  i    •      •  •   •          Otto* Work. 

Engineering  study  in  general  is,  in  my  opinion, 

more  important  for  the  prospective  school-teacher  of  physics 
than  special  research  in  pure  science. 

A  brief  course  in  mechanical  drawing,  and  another  in  the  use 
of  ordinary  wood-working  and  metal-working  tools,  should  be 
got  in  somehow,  in  the  summer  if  need  be,  unless  the  student 
is  already  tolerably  versed  in  these  arts ;  for  every  teacher  of 
physics  should  be  qualified  in  some  measure  to  describe  and 
make  apparatus.  The  habit  of  making  rather  careful  drawings 
approximately  to  scale,  in  the  designing  of  anything  to  be  con- 
structed, is  one  which  in  the  end  saves  time  and  trouble  and 
expense.  A  reasonable  acquaintance  with  tools  and  with  the 
processes  of  the  workshop  often  enables  one  to  foresee  and  to 
avoid,  without  sacrifice  of  anything  desirable,  difficult  and  ex- 
pensive manipulations  in  the  plans  which  at  first  occur  to  the 
designer.  How  to  make  things  with  the  least  labour,  if  he 
must  make  them,  how  to  get  the  most  for  his  money,  if  he 
has  money  to  spend,  are  questions  which  the  teacher  must 
ponder  well. 

A  moderate  degree  of  skill  in  a  few  of  the  simpler  operations 
of  glass-blowing  should  be  sought  by  observation  and  practice 
at  every  reasonable  opportunity,  and  in  general  the  n^t  of  Ob_ 
student  should  give  attention  not  merely  to  the  serration. 
main  tasks  which  are  plainly  set  before  him,  but  to  those 
sources  of  extraneous  information  and  experience  which,  if 
duly  cultivated,  will  yield  a  profitable  return.  The  habit  of 
general  observation,  not  of  everything  under  the  sun,  but  of 
what  will  bear  on  one's  professional  career,  cannot  be  formed 
too  early.  Fortunate  is  he  to  whom  this  habit  is  instinctive  ; 
but  he  to  whom  this  special  talent  is  not  given  need  not  despair. 


244  PREPARATION  FOR    TEACHING 

The  resolute  and  persistent  will,  this  is  the  potentiality  of  all 
talents. 

In  addition,  the  teacher  of  physics  should  know  something  of 
the  history  of  the  science  and  of  the  lives  of  the  men  who  have 
History  of  especially  developed  it.  A  class  is  always  interested 
Physics  and  to  hear,  for  example,  a  brief  account  of  the  long 

contest,  beginning  in  the  time  of  Newton,  which 
ended  in  the  final  establishment  of  the  undulatory  theory  of  light. 
Pupils  like  to  know  just  what  Galvani  was  doing  with  frogs' 
legs  when  he  made  his  immortal  discovery.  If  they  go  far 
enough  in  the  study  of  physics,  they  will  be  entertained  by  the 
British-German  controversy  over  the  merits  of  Mayer's  work  on 
the  mechanical  equivalent  of  heat.  It  is  well  also  to  explode  the 
myth  about  James  Watt  and  the  tea-kettle,  replacing  it  by 
the  sufficiently  interesting  true  account  of  his  development  of 
the  steam-engine. 

I  have  said  nothing  thus  far  concerning  the  study,  by  the  pros- 
pective teacher,  of  the  art  of  teaching  as  such.  In  common, 

probably,  with  most  college  teachers  of  physics,  I 
Art  of  hold  rather  conservative  views  in  regard  to  such 

study.  But  it  would  ill  become  one  who  is  writing 
a  book  on  the  art  of  teaching  physics  to  maintain  that  this  art 
cannot  be  profitably  studied  through  books  or  from  the  oral 
discourse  of  those  who  have  practised  it  long.  My  state  of 
mind  in  regard  to  this  matter  is  perhaps  one  which  may  as  well 
be  frankly  analyzed  here  and  now.  In  the  first  place,  I  have  my 
full  share  of  the  prejudice  created  against  "methods'7  by  the 
superficial,  ill-balanced  work  of  the  early  normal  schools.  In 
the  second  place,  I  hold  that  the  student  who  has  been  well 
taught,  has  necessarily  had,  along  with  his  conscious  instruction 
in  the  science  of  physics,  a  good  deal  of  possibly  unconscious 
instruction  in  the  art  of  teaching  physics.  In  the  third  place, 
I  have  some  apprehension  lest  the  conscious  study  of  this  art  will 
be  accompanied  by  an  over-conscious  attention  to  the  philoso- 
phy and  psychology  of  the  art,  with  the  possible  result  of  set- 
ting up  a  more  ponderous  system  of  mental  machinery  than  can 


PREPARATION  FOR    TEACHING  245 

be  used  to  advantage  in  the  very  practical,  common-sense  busi- 
ness of  teaching  young  people. 

The  students  in  any  training  school  or  college  will  perhaps  be 
more  exposed  to  this  danger  than  their  teachers  will  be ;  but 
even  the  teacher,  if  his  main  attention  is  directed  not  to  any 
science  as  such,  but  to  the  art  of  teaching  his  pupils  how  to 
teach  their  pupils  this  science,  if  he  habitually  looks  at  his  chem- 
istry or  his  physics  through  a  double  layer  of  more  or  less  opaque 
humanity,  even  the  teacher  runs  the  risk  of  ceasing  to  be  what 
he  ought  to  be,  a  chemist  or  a  physicist  with  an  inclination 
toward  pedagogy,  and  becoming  the  less  robust  individual  who 
may  be  described  as  a  pedagogist  with  an  inclination  toward 
chemistry  or  physics.  The  science  teachers  in  teachers'  colleges 
should  have  the  ability,  the  means,  and  the  opportunity,  for  doing 
some  original  work,  work  of  research,  in  their  sciences  as  such, 
without  any  regard,  for  the  time  being,  to  the  pedagogic  aspect 
of  their  profession,  but  with  every  sense  and  faculty  steeped  in 
the  atmosphere  of  pure  inquiry  and  bent  to  the  prosecution  of 
the  simple  scientific  end  proposed. 

The  art  of  teaching  is  now  receiving  a  great  deal  of  intelli- 
gent attention,  and  progress  is  evidently  being  made.  The  old 
normal  schools,  instead  of  being  abolished  as  useless,  have  been 
improved  and  are  therefore  growing  in  public  esteem.  Such  a 
school  as  the  very  flourishing  Teachers  College  of  Columbia 
University  is  an  experiment,  or,  rather,  an  experiment  station, 
which  must  be  watched  with  interest  by  intelligent  educators 
everywhere.  The  opportunity  of  beginning  one's  teaching  in 
a  moderate  way,  under  the  supervision  of  an  experienced 
teacher  and  frank  critic,  before  taking  the  full  and  permanent 
responsibility  of  conducting  a  class,  is  an  opportunity  to  be 
desired.  If  in  divinity  schools  there  is  place  and  use  for  courses 
in  "  Homiletics  and  Pastoral  Care,"  it  is  difficult  to  see  why, 
in  the  nature  of  things,  there  .should  not  come  to  be  in  the  for- 
mal training  of  the  teacher  a  place  and  use  for  courses  dealing 
with  the  technicalities  of  his  art  as  such.  I  observe,  however, 
that,  in  the  catalogue  from  which  I  have  taken  the  heading 


246  PREPARATION  FOR   TEACHING 

quoted  above,  this  heading  is  placed  over  the  very  last  division, 
except  elocution,  of  the  courses  of  instruction  open  to  students 
of  divinity.  The  learning,  the  science,  stands  foremost ;  then 
comes  the  art.  Thus  should  it  be  in  the  training  of  the 
teacher. 


CHAPTER   III 

THE    TEACHER   AS    STUDENT,   OBSERVER    AND    WRITER 
REFERENCES. 

Nichols,  E.  L.  Research  Work  for  Physics  Teachers.  SCIENCE,  Feb. 
8,  1901. 

IN  spite  of  what  I  have  said  in  the  preceding  chapter  con- 
cerning the  degree  of  Doctor  of  Philosophy,  I  do  not  wish 
to  discourage  those  who  feel  themselves  willing  and  able  to 
make  what  I  have  called  a  superfluity  of  preparation  for  the 
profession  of  teaching  in  schools.  To  some  men  the  labour 
of  scientific  research,  with  all  its  inevitable  drudgery,  with  all 
its  large  possibilities  of  negative  results,  is  a  joy  in  itself,  a 
passion  not  to  be  quenched  by  the  passage  of  years  or  by 
the  lack  of  visible  rewards  from  without.  If  a  man  has  this 
passion,  by  all  means  let  him  cherish  it  and,  so  far  as  he  can, 
gratify  it.  Let  him  go  on,  for  example,  to  the  attainment  of 
the  doctor's  degree,  and  then,  if  his  life-work  proves  to  be 
teaching  in  a  school,  let  him  preserve  there,  so  far  as  he  can 
without  neglect  of  his  first  duties,  his  ambition  and  his  habit 
of  scholarship. 

Will  such  a  man  find  opportunity  and  means  for  original  re- 
search while  engaged  in  school-teaching?     Perhaps  so.     The 
late  Professor  Rowland  once  asked  a  former  stu-   original 
dent  of  his  own  whether  he  was  doing  any  such  Researcll? 
work.     The  reply  was,  "  No,  I  have  n't  the  time,  and  I  have  n't 
the  money ;  "  whereupon  Rowland  exclaimed,  "  Don't  need  any 
time,    don't  need  any  money,  if  you  have  only  got  the  will." 
But  on  another  occasion,  when  he  was  asked  what  he  should 
do  with  his  students  while  making  his  researches,  he  replied,  "  I 


248  THE    TEACHER  AS  STUDENT 

shall  neglect  them,"  which  was,  in  a  way,  true.  It  was  well  for 
the  world  that  Rowland  did  neglect  his  routine  work,  and  he 
was  readily  forgiven  this  shortcoming ;  but  the  ordinary  doctor 
of  philosophy  must  not  expect,  because  he  will  not  be  able  to 
deserve,  a  like  indulgence. 

The  real  obstacle  to  research  by  teachers  is  not  so  much  lack 
of  time  and  means  for  laboratory  work,  as  lack  of  the  genius  for 
Professor  finding  the  right  thing  to  do,  and  lack  of  time  and 
Nichols's  opportunity  and  will  for  keeping  up  with  the  litera- 
ture of  research.  Successful  research  involves, 
first,  hitting  upon  some  more  or  less  important  problem ; 
second,  making  reasonably  sure  that  no  one  else  has  solved 
the  problem ;  third,  solving  it.  In  a  paper  read  before 
the  Physics  Club  of  New  York,  in  December,  1900,  and  pub- 
lished in  SCIENCE  for  February  8,  1901,  Professor  Nichols  of 
Cornell  has  discussed  the  possibilities  of  research  by  teachers 
in  a  very  interesting  and  suggestive  way.  I  cannot  help  think- 
ing, however,  that  this  paper  is  likely  to  be  of  more  use  to  college 
teachers  than  to  school-teachers  ;  for  very  few  men  who  have 
not  had  experience  and  training  in  research  during  their  stu- 
dent days  are  likely  to  cope  successfully  with  the  difficulties 
presented  even  by  the  apparently  simple  problems  which 
Professor  Nichols  mentions  as  within  the  reach  and  power 
of  teachers  in  schools. 

The  advice  given  by  Professor  Nichols,  that  every  teacher 
of  physics  should  habitually  read  either  SCIENCE  ABSTRACTS  or 
the  BEIBLATTER  to  the  ANNALEN  DER  PHYSIK,  as  well  as  some 
other  standard  journal  of  physics,  seems  to  me  excellent  in 
spirit  and  intention,  though  possibly  a  little  too  sweeping. 
Much  that  appears  in  these  periodicals  is  rather  discouragingly 
beyond  the  reach  of  the  school-teacher  of  physics  as  he  now 
exists,  or  as  he  is  likely  to  exist  for  some  years  to  come.  A  dry 
summary  of  highly  technical  papers,  often  contradicting  each 
other,  usually  given  without  authoritative  criticism  or  comment, 
can  be  inspiring  only  to  him  who  is  in  the  thick  of  research, 
and  able  to  give  much  of  his  time  to  reading  and  investigation. 


THE    TEACHER  AS  STUDENT  249 

Any  very  important  discovery  or  advance  in  physics  is  pretty 
sure  to  be  noticed  before  long  in  more  popular  publications. 
NATURE,  SCIENCE,  and  some  of  the  engineering  journals  will  be 
found  more  genial  and,  I  believe,  more  profitable  reading  than* 
the  ABSTRACTS  or  the  BEIBLATTER  by  most  teachers  in  schools 
at  present. 

It  is  of  doubtful  advantage  to  any  man  to  undertake  a  thing 
which  is  too  hard  for  him.  All  of  us  do  best  by  doing  well 
the  things  that  naturally  come  to  us,  from  circum-  wgrkakin 
stances  or  from  the  promptings  of  our  own  natures.  to  Research. 
The  surest  profit  of  research,  the  mental  and  moral  exercise 
and  enjoyment  of  it,  may  be  attained  in  full  measure  by  him 
who  has  no  thought  of  publication,  and  whose  only  conscious 
object  is  to  improve  the  quality  of  his  teaching.  Is  there  an 
habitual  experiment  or  an  habitual  laboratory  exercise  that 
goes  badly?  If  so,  just  there  lies  the  opportunity  and  the 
motive  for  research;  and -when  this  research  is  successfully 
ended,  not  only  the  teacher's  pupils  but  his  fejlow-teachers 
also  should  profit  by  it.  Is  there  spine  natural  phenomenon, 
within  doors  or  without,  in  the  sky,  the  air,  the  water,  the 
ground,  of  which  the  teacher  does  not  have  a  satisfactory  de- 
scription and  theory ;  just  there  is  the  occasion  for  first-hand 
observation  and  reflection,  perhaps  for  original  discovery.  The 
habit  of  really  looking  at  and  thinking  about  the  familiar  objects 
of  every-day  experience  is  sure  to  bring  usefulness  and  may 
bring  fame.  Some  men  have  this  habit  by  nature,  and  may 
even  suffer  from  a  too  miscellaneous  interest  in  what  goes  on 
about  them ;  but  others  must  deliberately  cultivate  the  habit, 
directing  it  toward  such  things  as  are,  from  a  professional  stand- 
point, important  for  them. 

I  shall  presently  give,  at  considerable  length,  examples  of  the 
problems,  essentially  problems  of  research,  which  every  teacher  of 
elementary  pnysics  will  find  in  his  laboratory  work,  and  of  the  way 
in  which  I  have  attacked  these  particular  difficulties.  I  say  "  at- 
tacked" advisedly,  for  I  do  not  claim  complete  victory,  or  a  fin- 
ished undertaking.  The  results  reached  in  this  endeavour  are  not 


250  THE   TEACHER  AS  STUDENT 

of  very  great  importance  in  themselves ;  but  they  will  illustrate 
well  enough  the  short  and  halting  forward  steps  by  which  pro- 
gress in  the  art  of  elementary  laboratory  teaching  is  made. 

Before  giving  these  illustrations,  which  will  make  the  next 
chapter,  I  wish  to  enumerate,  as  examples  of  the  things,  outside 
Physics  out  of  books,  which  may  profitably  engage  the  atten- 
of  Doors.  tjon  of  tne  teacher  or  his  pupils,  certain  objects 
and  phenomena  which  have  interested  me  during  a  recent  visit 
to  the  seashore.  These  are  :  The  waves  which  accompany  the 
progress  of  a  steamer  in  a  straight  line  through  a  smooth  sea, 
their  shape  and  succession,  the  surprising  length  of  time  after 
the  steamer  has  passed  before  they  reach  the  neighbouring 
shore,  the  ripple  mark  they  channel  in  the  sand  along  the  line 
where  each  advancing  wave  meets  its  retiring  predecessor  in  a 
swirl ;  the  bits  of  mirage,  by  which,  at  times,  distant  objects 
just  above  the  water-line  are  shown  double,  as  by  a  horizontal 
aerial  mirror,  and  the  distinction  between  such  reflection  and 
that  produced  by  the  water-surface ;  the  smooth  patches, 
"slicks,"  in  ruffled  water  and  their  probable  cause;  the  wind- 
ruffled  patches  in  smooth  water  and  the  frequent  slowness  of 
their  progress;  the  proper  angle  between  boom  and  keel  in 
sailing,  and  how  much  it  is  affected  by  friction  and  leeway ; 
the  floating  of  sand,  in  grains  and  patches,  inches  across,  on 
the  surface  of  calm  water;  the  functions  of  the  squid's 
mantle ;  the  differences  of  stroke  which  persons  of  different 
bodily  shape  must  use  in  swimming ;  the  best  position  of  the 
body  for  swimming  in  rough  water ;  the  presence  and  circula- 
tion of  fresh  water  in  the  sand  near  the  reach  of  the  tides. 

On  these  and  other  things  which  met  my  eye  and  held  my 
thought,  I  probably  made  no  observation  or  reflection  that  had 
not  been  made  a  thousand  times  before,  —  none  that  would  be 
worth  reciting  or  printing  at  any  length ;  but  my  days  were 
fuller,  my  enjoyment  wider  and  more  rational,  my  profit  greater, 
than  if  I  had  not  seen  them  and  thought  about  them. 

All  these  things  of  which  I  have  just  been  discoursing  at- 
tracted my  attention  during  a  vacation.  At  home  I  should  have 


THE    TEACHER  AS  STUDENT  251 

seen  few  of  them  and  perhaps  not  have  reflected  on  these  few. 
Change  of  scene,  variety  of  experience,  is  for  most  of  us  neces- 
sary, if  we  would  keep  our  faculties  awake.  An  change  and 
occasional  change  of  text-books,  for  the  mere  sake  Variety. 
of  refreshment  of  mind,  or,  better,  the  habitual  use  of  a  number 
of  text-books,  is  wise  and  wholesome.  The  habit  of  coming 
together  for  professional  consultation  with  other  teachers,  of 
visiting  their  laboratories  and  classes,  is  a  habit  to  be  resolutely 
maintained.  The  man  who  lives  too  much  within  himself,  who 
moves  within  too  narrow  limits  of  experience  and  thought,  soon 
comes  to  dread  contact  with  his  fellows,  to  shrink  from  new 
ideas  as  one  whose  limbs  are  cramped  shrinks  from  motion. 
When  the  teacher  finds  himself  in  this  condition,  he  must  rouse 
himself;  to  yield  is  for  him  to  become  an  old  man  at  once,  what- 
ever his  age  as  reckoned  by  the  calendar. 

Of  course,  he  must  not  give  up  his  professional  methods  and 
ideas  merely  because  they  are  questioned  or  criticised  or  de- 
nounced or  ridiculed.  He  must  rather  hold  himself  ready  to 
defend  them,  so  long  as  he  believes  them  worthy  of  defence  ; 
but  in  order  to  do  this  he  must  be  willing  to  hear  what  is  said 
against  them.  Few  men,  I  take  it,  like  to  be  made  a  target  by 
critics  or  adversaries ;  but  those  who  cannot  bear  it  must  be 
content  to  remain  unseen. 

The  practice  of  writing  for  publication  is  to  be  commended 
for  the  teacher,  provided  there  is  some  professional  matter  in 
which  he  believes  himself  able  to  interest  and  in-  writing  and 
struct  his  fellow-teachers  or  the  public  at  large.  It  Speaking. 
is  true  that  his  judgment  of  what  is  interesting  and  instructive 
may  not  always  be  confirmed  by  that  of  editors,  especially  of 
editors  who  pay  for  what  they  accept ;  and  it  is  doubtless  true 
that  no  form  of  rejection  sufficiently  suave  to  be  quite  satisfac- 
tory to  the  author  of  the  rejected  manuscript  has  yet  been 
found;  but,  nevertheless,  writing  is  good  for  the  writer.  It 
compels  him  to  think  clearly  where  he  may  have  thought 
vaguely ;  it  keeps  his  attention  on  the  theme  discussed  and 
rouses  thoughts  he  never  knew  before  or,  knowing,  has  forgotten. 


252  THE    TEACHER  AS  STUDENT 

Even  the  rejection  of  his  offering  by  some  hard-headed,  if  not 
hard-hearted,  editor  may  be  salutary,  impelling  him  to  cultivate 
a  livelier  habit  of  thought  and  a  better  style  of  expression.  Such 
excellence  of  language,  in  speech  and  writing,  as  the  teacher 
may  readily  be  capable  of,  he  should  habitually  maintain  ;  for  a 
good  style  is  more  intelligible,  as  well  as  more  pleasing,  than  a 
bad  one.  Every  English-speaking  teacher  should  be,  directly 
or  indirectly,  a  teacher  of  English. 


CHAPTER  IV 

PROBLEMS  OF  LABORATORY  PRACTICE 
REFERENCES. 

SCHOOL  SCIENCE.  Chicago.  Zeitschrift  fur  den  physikalischen  und 
chemischen  Unterricht,  Berlin. 

IN  this  chapter  I  have  brought  together  accounts  of  attempts 
recently  made  to  improve  in  certain  respects  the  work  done  in 
one  of  my  laboratory  classes,  work  similar  to  that  of  the  physics 
classes  in  many  secondary  schools.  I  give  these  accounts  as 
showing  the  kind  of  work,  original  in  its  way,  in  which  any 
teacher  may  employ  his  energy  for  the  betterment  of  his  art. 

On   Water-Proofing   Wooden    Blocks. 

In  elementary  laboratory  work  it  is  a  common  practice  to  put 
wooden  blocks  or  rods  into  water,  and  for  such  purposes  that  any 
considerable  amount  of  soaking  would  be  decidedly  objection- 
able. A  simple,  easily  applied,  and  thoroughly  effectual  method 
of  water-proofing  is,  I  fear,  still  to  be  discovered.  Paint,  in 
a  very  thick  coat,  would  doubtless  protect  the  blocks  for  a  time  ; 
but  painted  blocks  would  be  rather  unsightly,  and,  moreover, 
the  paint  would  come  off  in  the  hard  usage  of  elementary  labo- 
ratory work.  Similar  objections  apply  to  any  form  of  varnish- 
ing that  would  really  keep  out  the  water.  Impregnating  the 
wood  with  paraffin  seems  to  be,  on  the  whole,  the  best  device. 
There  are  various  ways  and  degrees  of  doing  this,  and  I  have 
been  in  doubt  until  recently,  as  many  teachers  may  still  be  in 
doubt,  as  to  the  relative  efficiency  of  these  various  practices. 

From  my  experiments  in  water-proofing  cherry-wood  blocks, 
I  have  come  to  the  conclusion  that,  for  ordinary  laboratory 
purposes,  the  use  of  an  exhaust  pump  to  draw  out  the  air  from 


254      PROBLEMS  OF  LABORATORY  PRACTICE 


a  block  submerged  in  very  hot  paraffin  is  not  necessary,  but 
that  it  is  well  to  allow  the  block  to  remain  buried  in  the  paraf- 
fin while  cooling.  A  block  about  9  cm. 
long,  with  the  grain,  and  about  4  cm.  by 
3  cm.  across  the  grain,  treated  in  this 
way,  absorbed  about  2.7  gm.  of  paraffin, 
increasing  in  weight  from  58.1  gm.  to 
60.8  gm.  Later,  submerged  in  water, 
this  block  gained  in  weight  about  0.8 
gm.  in  4^  hours  and  2.1  gm.  in  17^ 
hours. 

As  a  result  of  this  study,  I  have  had 
constructed,  for  the  purpose  of  water- 
proofing wooden  blocks  of  a  familiar 
size,  about  7.5  cm.  square  by  3.8  cm. 
thick,  a  copper  trough  25  cm.  long,  9 
1 3  cm.  deep, 


Fig.l 


Fig.2. 


cm.   wide,  and   about 
slightly  rounded  at  the  bottom  so  as  to  allow  free  movement 
of  paraffin  beneath  the  blocks.     Across  each  end  of  the  trough, 
and  extending  a  little  below  the  bottom,  is  soldered  a  metal  bar, 
the    ends    of   which   project    on 
either    side.       These     crossbars 
serve  as  a  support  for  the  trough 
when  it  is  placed,  for  cooling,  in 
water.     For  heating,  the  trough 
is  supported  by  resting  the  ends 
of  the  crossbars  in  slots  at  the 
top  of   brass  posts  reaching  up 
from  a  broad  wooden  base,  the 
height  being  so  adjusted   as  to 
adapt  it  to  the  use  of  a  Bunsen 
burner. 

Fig.  i  shows  an  end  view  of  

the  trough  on  its  support.    Fig.  2 

shows  one  end  of  wooden  base  as  seen  from  above.  Fig.  3 
shows  how,  by  means  of  a  brass  strip,  ss,  properly  shaped,  the 
blocks  may  be  prevented  from  floating  in  the  melted  paraffin. 


PROBLEMS  OF  LABORATORY  PRACTICE      255 

The  following  seems  to  be  a  good  method  of  procedure. 
Melt  enough  paraffin  in  the  trough  to  have  a  depth,  before  the 
blocks  are  put  in,  of  about  4  cm.,  and  bring  this  to  a  temper- 
ature of  about  1 00°  C.  Put  in  six  blocks,  each  having  a  stout 
wire  twisted  around  it  to  separate  it  from  its  neighbours  and 
to  serve  as  a  handle  for  lifting  it  from  the  trough ;  put  in  the 
brass  strip,  ss,  Fig.  3  ;  heat  the  bath  again  to  100°  C. ;  lift  the 
trough  from  its  support  and  stand  it,  or  float  it,  in  a  large  tank 
of  cool  water ;  after  the  trough  has  been  in  the  water  half  an 
hour  or  more,  remove  it  from  the  tank,  lift  out  the  blocks, 
which  will  doubtless  be  covered  in  part  by  solid  paraffin,  and 
wipe  them  carefully  while  the  wax  is  still  soft.  In  order  to  take 
out  the  blocks  with  ease,  it  will  probably  be  necessary  to  apply 
the  flame  for  a  little  while  to  the  bottom,  sides,  and  ends  of  the 
trough. 

On  the  Use  of  the  Spring-Balance. 

The  spring-balance  deserves  and,  I  must  admit,  needs  some 
words  of  defence  and  exposition  from  its  friends.  It  is  so  in- 
expensive, so  convenient,  so  quick  in  its  action,  that  I  make 
very  much  use  of  it,  in  spite  of  its  exasperating  inaccuracy  in 
its  native  state.  This  inaccuracy  is,  of  course,  due  to  the 
cheapness  of  its  construction,  the  price  at  which  it  is  sold  not 
warranting  the  adaptation  of  the  scale  of  each  balance  to  the 
idiosyncrasies  of  its  spring,  so  that  the  faces  are  merely  stamped 
in  divisions  corresponding  more  or  less  closely  to  the  behaviour 
of  the  average  spring ;  and,  beyond  that  measure  of  adjustment, 
agreement  of  spring  and  scale  is  a  matter  of  luck. 

I  have,  in  the  Harvard  Descriptive  List,  written  out  with  care 
directions  for  studying  inaccuracies  of  the  scale  and  recording 
them  in  a  graphical  form.  But  further  experience  and  re- 
flection have  convinced  me  that  the  best  thing  to  do  with  an 
incorrect  scale  is  to  cover  it  with  paper,  fastened  on  with 
mucilage  after  the  face  of  the  scale  has  been  cleaned  and 
slightly  roughened  with  rather  coarse  emery,  and  mark  a  new 
and,  as  nearly  as  may  be,  correct  scale  on  this  paper.  To  do 


256      PROBLEMS   OF  LABORATORY  PRACTICE 


this  successfully,  well  enough  at  least  to  improve  greatly  the 
graduation  of  many  balances,  is  an  exercise  not  too  long  or  too 
difficult  for  a  rather  young  class.  The  following  method  works 
well :  Cover  the  scale  of  the  balance,  which  we  will  suppose  to 
be  one  of  the  very  familiar  25o-gm.  instruments  marked  off  in 
lo-gm.  divisions,  with  paper  fastened  on  with  mucilage.  Cut 
a  thin  strip  of  spring  brass  to  the  shape  shown  in  Fig.  4,  the 
scale  of  which  is  */£  ;  bend  this  strip  sharply  and  carefully  along 
the  dotted  line  dd,  and  so  shape  it  that,  when  this  bend  is 
fitted  to  the  edge  of  the  balance  case,  the  end  ee  will  clasp  the 
back  of  the  case  with  some  firmness,  as  in  Fig.  5.  The  part 
dc  should  be  of  such  length  that  c  will  nearly  touch  the  index  of 


d  c 


Fig.  4. 


Fig-  5- 


Fig.  6. 


the  balance  when  the  two  are  on  the  same  level,  as  in  Fig.  6. 
Now  suspend  the  balance  in  a  free  vertical  position,  without 
load,  and  slide  the  spring-brass  clasp,  which  should  grip  the 
case  firmly  enough  to  stay  in  position  wherever  placed,  up  or 
down  until  one  edge  is  in  line  with  the  significant  part,  point 
or  line,  of  the  index,  or,  rather,  make  the  adjustment  in  such  a 
way,  that,  when  a  fine  pencil  line  is  made  along  one  horizontal 
edge,  this  mark  will  be  in  line  with  the  significant  part  of  the 
index.  After  this  zero  line  is  drawn,  put  on  a  lo-gm.  load, 
make  a  new  adjustment  of  the  slider,  draw  the  corresponding 
line,  etc.  A  graduation  made  in  this  way  ought  not  to  be 
wrong  at  any  mark  more  than  i-gm.  Change  of  performance 
of  the  spring,  from  rust  or  other  causes,  may  in  time  invalidate 
this  graduation,  but  it  will  always  be  easy  to  make  a  new  one. 
It  must  be  granted  that,  even  after  the  scale  has  been  cor- 


PROBLEMS  OF  LABORATORY  PRACTICE      257 

reeled,  the  pupil  can  easily  make  errors  in  the  use  of  the  spring- 
balance,  and  that,  in  fact,  he  must  look  with  some  care  in  order 
not  to  make  errors  of  a  gram  or  more  in  his  readings.  I  do 
not,  however,  consider  this  an  objection  to  this  form  of  balance. 
The  habit  of  intelligent  care  is  one  of  the  most  important  ob- 
jects to  be  attained  in  the  study  of  physics  or  in  any  other  study. 
A  boy  who  is  unwilling  or  unable  to  read  such  a  spring  balance 
as  I  have  described,  on  which  the  lo-gm.  divisions  are  about 
0.2  cm.  long,  without  commonly  making  an  error  exceeding  i 
gram,  is  not  fit  to  use  a  beam-balance ;  for  the  latter,  though 
far  more  sensitive  than  the  spring-balance,  is  no  automaton 
miraculously  contrived  to  prevent  the  natural  consequences  of 
stupidity  and  carelessness.  In  order  to  yield  good  results  in 
the  hands  of  some  boys,  a  piece  of  apparatus  must  have  such 
cunning  that  it  will  not  permit  itself  to  be  set  wrong  or  read 
wrong,  and  such  vigour  of  constitution  that  it  will  not  mind 
being  knocked  off  the  table  occasionally. 

In  studying  the  parallelogram  of  forces,  some  teachers  use 
weights  suspended  by  cords  passing  over  pulleys,  the  latter 
being  attached,  but  movable,  along  the  edge  of  a  round  table. 
The  friction  of  the  pulleys  and  the  need  of  a  table  of  peculiar 
form  seem  to  me  objections  to  this  device.  Spring-balances, 
correctly  graduated,  are,  I  believe,  preferable  in  this  experiment. 

On  the  Use  of  the  Platform-Balance. 

Double-platform  balances,  costing,  with  weights,  about  $7.00, 
weighing  anything  up  to  a  kilogram,  with  an  ostensible  accuracy 
of  o.i  gm. ,  are  very  common  and  extremely  useful  pieces  of 
laboratory  equipment.  Unfortunately,  they  do  not  always  live 
up  to  their  professions ;  and  I  never  feel  quite  sure  of  the  last 
tenth  of  a  gram,  even  if  the  set  of  weights  accompanying 
the  balance  is  correct  within  that  limit,  which  is  usually  more 
than  doubtful.  There  are  some  experiments,  which  I  like 
to  give,  in  which  a  change  of  o.i  gm.  in  the  weight  of  some 
heavy  body  is  rather  important ;  and  yet,  for  use  in  such  experi- 


258      PROBLEMS   OF  LABORATORY  PRACTICE 

ments,  I  know  nothing  which,  all  things  considered,  is  likely 
to  replace  this  balance,  with  all  its  faults. 

As  the  absolute  weight  of  the  body  dealt  with,  in  the  experi- 
ments just  mentioned,  is  usually  a  matter  of  small  importance, 
provided  its  change  of  weight  during  an  experiment  can  be 
correctly  found,  inaccuracies  of  the  metal  weights  used  are 
not  likely  to  be  troublesome,  provided  the  large  weights,  in 
which  the  perceptible  errors  are  likely  to  exist,  remain  in  use 
during  the  whole  operation.  The  most  serious  causes  of  error, 
and  the  means  for  avoiding  them,  are  perhaps  sufficiently  indi- 
cated in  the  following  set  of  rules  for  the  use  of  the  kind  of 
balance  now  under  discussion : 

Directions  for  the  Use  of  the  Double-Platform  Balance. 

i.1  When  it  is  necessary  to  weigh  an  object  to  a  fraction  of 
a  gram  on  this  balance,  a  vertical  scale  should  be  placed  on  the 
table  alongside  the  outer  edge  of  one  platform,  and  the  balance 
should  be  regarded  as  in  equilibrium  only  when  the  edge  of 
the  platform  is  level  with  some  particular  mark  on  this  scale. 

2.  Before  making  any  weighing,  be  sure  that  the  balance  is 
in  equilibrium,  with  no  load  on  either  platform,  and  with  the 
sliding  weight  at  zero.     This  test  should  be  repeated  frequently 
during  the  use  of  the  balance. 

3.  Put  the  object  to  be  weighed  at  the  middle  of  the  left- 
hand  platform.     Put  the  weights,  especially  the  large  ones,  as 
nearly  as  may  be  at  the  middle  of  the  right-hand  platform. 

4.  Any  heavy  shock  suffered  by  the  balance  is  likely  to  put 
the   bearings   temporarily  out  of  order,  enough  to   affect  the 
weighings  perceptibly.     Such  a  shock  is  most  often  given  by 
unloading  one  platform  while  the  other  remains  loaded.     When 

1  Section  i  of  these  directions  has  reference  especially  to  balances 
of  the  old  pattern  without  pointer.  Many  balances  now  have  pointers, 
but  rather  unsatisfactory  ones.  If  the  ordinary  pointer  were  doubled 
in  length,  and  brought  to  a  sharp  tip  close  to  the  scale,  which  should 
be  reduced  to  a  single  well-defined  mark,  there  would  be  no  need  of 
Direction  i. 


PROBLEMS  OF  LABORATORY  PRACTICE      259 

the  load  of  either  platform  is  to  be  removed  or  much  changed, 
the  other  platform  should  first  be  pushed  down  as  far  as  it 
will  go. 

5.  If  the  balance  has  by  any  accident  suffered  a  disturbing 
shock,  the  bearings  should  be  worked  back  into  good  condition 
by  pressing  firmly  down  on  both  platforms  and  then  rocking 
them  up  and  down  several  times. 

6.  There  may  be  small  differences  between  large   weights 
which  are  marked  alike.     Therefore,  in  any  case  where  a  small 
change  in  the  weight  of  some  heavy  object  is  looked  for,  as 
in  Exercise  34  (of  the  list  given  in  Chapter  X.),  on  the  Density 
of  the  Air,  or  in  Exercise  52,  be  careful  to  use  the  same  large 
weights  in  all  the  weighings. 

7.  Take  great  care  to  let  no  mercury  come  into  contact  with 
brass  weights.    Mercury  is  often  carried  as  a  film  on  the  fingers, 
and  is  usually  to  be  found  in  small  beads  on  the  table-top. 

8.  Always  replace  the  weights  in  their  proper  holders  when 
the  weighings  are  finished. 

Measurement  of  the  Expansion  of  Air. 

I  have  been  from  the  first  much  interested  in  those  two 
exercises  of  the  Harvard  Descriptive  List  which  undertake 
to  measure  the  two  coefficients  of  expansion  of  air,  and 
have  been  somewhat  disappointed  at  the  comparative  neglect 
of  them  in  the  schools.  I  must  confess,  however,  that  they 
present  some  difficulties,  and  that  the  results  obtained  from 
them  by  my  own  classes  have  not  been  always  satisfactory. 
And  yet,  I  am  so  fully  persuaded  of  the  importance  of  these 
exercises,  that,  instead  of  giving  them  up,  I  have  lately  revised 
pretty  thoroughly  their  details,  in  the  hope  of  making  the  work 
easier  and  the  results  better. 

The  glass  tube  which  is  to  contain  the  imprisoned  column  of 
dry  air  should  be  at  the  start  about  45  cm.  long.  The  diame- 
ter of  its  bore  should  be  about  0.15  cm.;  for,  if  it  is  much 
smaller  than  this,  the  capillary  effect  on  the  mercury  column 
which  confines  the  air,  which  effect  will  rarely  be  quite  the 


260      PROBLEMS   OF  LABORATORY  PRACTICE 

same  at  both  ends  of  the  column,  may  prove  troublesome,  and, 
if  it  is  much  larger  than  this,  the  mercury  column  is  likely  to 
break,  especially  in  transportation. 

Comparative  calibration  of  different  parts  of  the  tube  is 
needed  for  satisfactory  measurement  of  the  expansion  of  air 
Calibration  under  constant  pressure.  If  tubes  could  readily 
of  Tube.  be  found  in  which  the  increase  of  length  of  the 
air  column,  during  heating  at  constant  pressure,  would  occur 
in  a  part  of  the  bore  differing  not  more  than  i  per  cent  in 
cross-section  from  the  part  occupied  before  expansion,  it  would 
hardly  be  worth  while  to  keep  a  detailed  record  of  the  calibra- 
tion. But,  as  this  standard  of  uniformity  cannot  well  be  main- 
tained, a  record  of  the  calibration  should  be  kept,  and  each 
tube  in  its  finished  condition  should  be  accompanied  by  such  a 
record,  which  may  well  be  in  the  form  indicated  by  Fig.  7. 


20.00  9.SQ  9.95  3.60 

Fig.  7- 

This  would  mean  that  a  certain  mercury  column  was  9.80  cm. 
long  when  its  middle  was  at  a  point  indicated  by  the  dot  nearest 
the  now  sealed  end  of  the  tube ;  that  the  same  column  was 
9.85  cm.  long  when  its  middle  was  at  the  point  marked  by  the 
next  dot,  and  so  on.  Expansion,  during  heating  at  constant 
pressure,  will  in  this  tube  take  place  mainly  or  wholly  in  the 
section  between  the  point  marked  9.90  and  that  marked  10.00. 
The  mean  length  of  the  calibrating  column  in  the  three  right 
hand  sections  being  9.85,  the  variation  of  bore  of  the  tube  will, 
if  neglected,  cause  an  error  of  about  10  parts  in  1000,  or 
i  per  cent,  in  the  value  of  the  coefficient  of  expansion  calcu- 
lated from  the  observations  at  constant  pressure.  If  the  cali- 
brating is  well  conducted  and  recorded,  still  less  uniform  tubes 
than  the  one  here  imagined  may  well  be  used,  proper  correction 
being  made  for  the  variation  of  bore. 

The  outer   diameter  of  the  tube  should  be   about  0.6  cm. 
This  will  insure  sufficient  strength  and  will  make  a  good  but 


PROBLEMS  OF  LABORATORY  PRACTICE      261 

not  too  tight  fit  where  the  tube  is  pushed  through  a  0.5-0111. 
hole  in  a  rubber  stopper,  as  it  will  be  in  use  after  completion. 
The  companion  glass  tube,  which  will  be  connected  Diameter  of 
with  the  one  already  described  and  will  contain  the  Tut)e* 
outer  end  of  the  mercury  column,  will  be  called  the  outer 
tube  or  the  open  tube.  This  outer  tube  should  be  at  least  50 
cm.  long,  but  in  other  dimensions  as  like  as  may  be  to  the 
inner  tube  which  is  to  contain  the  imprisoned  air.  The  outer 
and  the  inner  tubes  are  to  be  connected  by  a  piece  of  antimony 
rubber  tubing  about  6  cm.  long,  0.3  cm.  in  diameter  of  bore, 
and  0.8  cm.  in  outside  diameter.  Into  this  tube  each  of  the 

glass  tubes  should  extend  about  i.c  cm.,  leaving 

.  .  Connections, 

about  3  cm.  clear.     This  arrangement  will  enable 

us  to  place  the,glass  tubes  at  right  angles  with  each  other,  as  in 
Fig.  10,  without  danger  of  collapsing  the  rubber  connection. 
The  bore  of  the  rubber  tube  being  much  larger  than  the  bore  of 
the  glass,  four  times  as  large,  in  cross-section,  we  will  suppose, 
a  sort  of  pocket  will  exist  between  the  glass  tubes,  which  must 
be  remembered  in  the  operation  of  filling. 

This  operation  is  one  of  critical  importance,  for  if  it  is  not 
properly  done,  insuring  dry  air  for  the  expansion,  the  apparatus 
is  worse  than  useless.  It  is,  of  course,  not  enough  care  in 
merely  to  make  sure  that  there  is  no  visible  mois-  Drying. 
ture  in  the  tubes.  Care  must  be  taken  that  no  invisible  layer 
of  water,  sufficient  to  produce  any  considerable  pressure  of 
vapour  on  evaporation,  exists  within  the  closed  air  space  after 
the  filling.  It  is  practically  impossible  to  dry  out  a  small-bore 
tube  after  one  end  is  sealed.  For  sure  effects,  dry  air  must  be 
drawn  through  the  tube  while  it  is  hot,  and  this  process  should 
continue  for  some  little  time,  several  minutes  at  least.  The 
heating  is  readily  accomplished  by  means  of  a  steam  jacket 
(Fig.  8),  about  36  cm.  long,  that  is,  about  4  cm.  shorter  than 
the  finished  sealed  tube  is  to  be.  The  air  is  well  enough 
dried  by  making  it  bubble  gently  through  eight  or  ten  centi- 
meters of  sulphuric  acid  among  glass  beads. 

In  preparation  for  filling,  take  the  selected  and  calibrated  tube 


262      PROBLEMS  OF  LABORATORY  PRACTICE 


which  is  to  contain  the  air  and,  applying  to  it,  5  cm.  from  one 
end,  a  slender  gas  flame  (through  a  burner  consisting  of  a  piece 
Making  °f  glass  tubing  2  or  3  cm.  long  and  about  0.05  cm. 

Connections.  m  diameter  of  bore),  reduce  the  diameter  to  about 
one  third  of  its  original  size,  making  this  reduction  affect  as  little 
as  may  be  of  the  length  of  the  tube.  Place  the  tube  in  the 
heating  jacket  and  connect  it  with  its  companion  glass  tube  by 
means  of  the  rubber  tube  already  described,  taking  care  that 
there  be  no  visible  moisture  in  any  of  these  tubes  when  they  are 
put  together.1  Connect  at  the  left,  Fig.  8,  with  an  aspirator 

JL 


Fig    8. 

pump.  Connect  the  drawn-out  end  of  the  air-tube,  at  the  right 
in  Fig.  8,  with  the  drying  bottle.  Especial  care  should  be  taken 
to  have  the  junctions  between  rubber  and  glass  tight,  other- 
wise steam,  escaping  from  the  heating  jacket,  may  be  drawn 
into  the  tube  by  way  of  these  junctions. 

Let  steam  flow  through  the  jacket,  and  draw  air  through  the 
heated  glass  tube  at  the  rate,  let  us  say,  of  i  cu.  cm.  per  second, 
Process  of  to  be  estimated  roughly  by  means  of  the  bubbles 
Drying.  rising  from  the  acid  in  the  drying  bottle.  The 

arrangement  thus  far  is  indicated  by  Fig.  8,  which  shows  a 


1  It  is  well  to  have  a  tiny  wad  of  cotton  in  each  end  of  the  main  tube 
while  it  is  being  put  into  the  heating  jacket ;  for  this  jacket,  as  well  as 
the  stoppers  at  its  ends,  through  which  the  glass  tube  must  extend,  is 
likely  to  be  wet,  and  without  precaution  water  may  thence  enter  the  glass 
tube. 


PROBLEMS  OF  LABORATORY  PRACTICE      263 

device  for  relieving  the  reduced  section  of  the  glass  tube  from 
the  weight  of  the  connections.  The  arrow  indicates  the  course 
of  the  air  coming  from  the  drying  bottle. 

Maintain  this  condition  of  things  ten  minutes ;  then  discon- 
nect the  pump.     Apply  the  small  flame  once  more  to  the  nar- 
rowed section  of  the  glass  tube  until   this  is  melted  off  and 
neatly  sealed.    Allow  a  little  time   Sealing 
for  the  glass  to  cool  after  the  ap- 
plication of  the  flame  and  then  withdraw  it 
from    the    steam   jacket,   keeping   it    all   the 
time  connected  with  its  companion  tube.    Of 
course  the  heated  tube  in  cooling  draws  in 
some  air  from  the  outer  tube  or  the  rubber 
connection,  but,  as  this  air  has  been  dried,  it 
will  do  no  harm.    The  undried  air  of  the  room 
will  enter  the  outer  tube  only.     It  is  probable 
that  the  inner  tube  would  acquire  no  injurious 
amount  of  vapour  if  the  operation  of  intro- 
ducing the  mercury  were  deferred  for  some 
days    or   even  weeks,  though,   if  this   delay 
were  to  occur,  it  would  be  safer  to  detach  the 
inner  glass  tube  from  the   rubber  connector 
and  seal   its  open  end  with  paraffin  for  the 
time    being.     Dry  air  should,  in    this   case, 
be   drawn    through    the    connector  and    the 
outer  tube   before   reconnecting   for  further 
operations. 

The  business  of  putting  in  the  mercury  is 
facilitated  by  the  use  of  a  mercury  bottle,  or 
reservoir,  having  a  side  opening  introduction 
near  its  bottom,  as  in   Figs.    10  of  Mercury, 
and  ii.     The  tube  to  be  filled,  being  con- 
nected  with   this   opening,  will   receive   the 
mercury  horizontally,  under  a  pressure  which 
need  differ  but  little  from  that  of  the  atmos- 
phere, —  a  condition  of  things  which  make  it  Flg*  9- 


264      PROBLEMS  OF  LABORATORY  PRACTICE 

easy  to  control  with  considerable  nicety  the  amount  of  air  to 
be  left  in  the  tube.  This  is  an  important  consideration ;  for, 
if  too  little  air  remains,  small  errors  of  volume  become  im- 
portant ;  and,  if  too  much  air  remains,  expansion  at  constant 
pressure  may  reach  beyond  the  limit  of  the  inner  tube. 

Connect,  then,  the  tube,  the  mercury  bottle,  a  pressure- 
gauge  and  the  aspirator  air-pump,  according  to  the  indications 
Adjustment  °^  ^&'  9>  wmcn  represents  the  bottle  lying  on  its 
of  Air-  side  and  does  not  undertake  to  show  the  method 

by   which   it   is    fastened   to   its   support.     Before 
the  pump  is  set  in  operation,  a  rough  calculation  should   be 


Fig.  10. 

made  of  the  degree  of  exhaustion  required.  Let  us  suppose 
that  the  closed  tube  is  40  cm.  long,  the  rubber  connection 
equivalent  in  capacity  to  1 2  cm.  of  the  glass,  the  outer  tube, 
of  same  bore  as  the  sealed  tube,  50  cm.  long,  making  a  total  of 
102  cm.  We  wish  to  have  the  imprisoned  dry  air  column,  at 
atmospheric  pressure  and  ordinary  temperature,  about  26  cm. 
long.  Accordingly,  before  admitting  mercury  to  the  outer  tube, 
we  should  reduce  the  air  pressure  within  the  tube  to  26  /  102  of 
the  barometic  pressure,  about  19  cm.  It  is  well,  however,  to 
make  a  first  trial  with  a  somewhat  greater  pressure ;  for  it  is 
better  to  take  out  too  little  air  at  first  than  too  much.  When, 
therefore,  the  gauge  indicates  about  21  cm.  pressure,  close  the 
pinch-cock  c,  disconnect  with  the  pump  beyond  <:,  tip  the  bottle 


PROBLEMS  OF  LABORATORY  PRACTICE      265 

up  into  the  position  shown  by  Fig.  10,  thus  bring  the  mercury 
over  the  end  of  the  tube,  lift  the  sealed  tube  to  a  vertical  posi- 
tion, as  in  the  figure,  so  that  the  mercury  entering  will  leave  no 
air  bubbles  in  the  rubber  connector,  and  then  open  the  pinch- 
cock,  letting  the  air  in  rather  slowly.  When  equilibrium  is 
reached,  lay  the  sealed  tube  horizontal,  as  in  Fig.  n,  and 


Fig.  ii. 

measure  the  length  of  the  imprisoned  air-column.  If  this  is  more 
than  27  cm.  long,  it  will  be  well  to  take  out  a  little  more  of  the 
air,  for  which  operation  the  position  of  Fig.  9  should  be  re- 
sumed. If  the  length  of  the  air-column  proves  to  be  between 
24  cm.  and  27  cm.  long,  it  is  well  enough,  and  the  tube  should 
be  disconnected  from  the  bottle,  the  apparatus  being,  for  this 
operation,  laid  on  its  side,  as  in  Fig.  12,  in  order  to  avoid 


Fig.  12. 

spilling  mercury.  A  part  of  the  mercury  in  the  outer  tube 
should  now  be  allowed  to  run  out,  so  that  the  column  finally 
left  in  it,  when  the  whole  is  laid  horizontal,  shall  be  not  far 
from  35  cm.  long.1 

1  I  have  lately  tested  23  tubes  prepared,  either  by  myself  or  under  my 
supervision,  in  general  accordance  with  the  directions  here  given.  Two 
of  them  were  bad,  giving  more  than  .004  for  a,  the  coefficient  of  pressure 
increase.  This  probably  indicated  incomplete  drying,  due,  perhaps,  to 


266      PROBLEMS   OF  LABORATORY  PRACTICE 

If  manufacturers  would  properly  select,  calibrate,  clean,  dry 
out  and  seal  the  tubes,  and  close  one  end  temporarily  with 
Calibration,  paraffin  (see  p.  263),  it  would  be  an  easy  matter 
etc.,  by  Man-  for  teachers  to  fill  them.  This  division  of  labour 
would  avoid  the  danger  of  breaking,  to  which  the 
mercury  column  is  subject  during  transportation. 

some  carelessness  in  following  directions.  The  others  gave  for  a, 
values  ranging  from  .00356  to  .00379,  the  mean  being  .00366.  Most  of 
the  variation  was  probably  due  to  inequality  of  capillary  effects  at  the 
hot  and  cold  ends,  respectively,  of  the  mercury  column.  Each  end  of 
this  column  should  be  jarred  smartly  just  before  readings  are  made. 


CHAPTER  V 

SCHOOL  TEXT-BOOKS   OF   PHYSICS 

REFERENCES. 

This  list  is  made  up  of  general  text-books  intended  for  school  use, 
most  of  which  include  or  have  reference  to  directions  for  a  course  of 
laboratory  work  to  be  done  by  the  pupils.  Laboratory  manuals,  as  dis- 
tinguished from  text-books,  special  treatises  on  parts  of  physics,  and 
general  text-books  suitable  for  the  use  of  teachers  rather  than  pupils,  will 
be  named  later  in  connection  with  Chapters  VIII.  and  X. 

Avery,  E.  M.  Elementary  Physics.  New  York,  Butler,  Sheldon,  & 
Co.  School  Physics.  Same  author  and  publisher. 

Carhart  and  Chute.  High  School  Physics.  Boston,  Allyn  &  Bacon. 
1902.  Pp.  433. 

Cooley,  L.  B.  C.  Student's  Manual  of  Physics,  New  York,  Ameri- 
can Book  Co. 

Crew,  Henry.  Elements  of  Physics.  London  and  New  York,  Mac 
millan.  1900.  Pp.  353. 

Gage,  A.  P.     Boston,  Ginn  &  Co. 

Elements  of  Physics.     1898.     Pp.  381. 

Introduction  to  Physical  Science.    1896.     Pp.  374. 

Principles  of  Physics.     1895.     Pp-  ^34- 

Gilley,  F.  M.  Principles  of  Physics.  Boston,  Allyn  &  Bacon.  1901. 
Pp.  552. 

Hall,  E.  H.  and  Bergen,  J.  Y.  Text-book  of  Physics.  New  York, 
Henry  Holt  &  Co.  1897.  Pp.  596. 

Henderson,  C.  H.  and  Woodhull,  J.  F.  Elements  of  Physics.  New 
York,  D.  Appleton  &  Co.  1900.  Pp.  388. 

Hoadley,  G.  A.  Brief  Course  in  General  Physics.  New  York, 
American  Book  Co.  1900.  Pp.  463. 

Nichols,  E.  L.  The  Outlines  of  Physics.  London  and  New  York, 
Macmillan.  1897.  Pp.  452. 

Rowland,  H.  A.  and  Ames,  J.  8.  Elements  of  Physics.  New  York, 
American  Book  Co.  1900.  Pp.  252. 

Stone,  W.  A.  Experimental  Physics.  Boston,  Ginn  &  Co.  1897. 
Pp.  378. 

Thwingf  C.  B.  An  Elementary  Physics.  Boston,  Sanborn  &  Co. 
1900.  Pp.  371. 


268          SCHOOL    TEXT-BOOKS  OF  PHYSICS 

Wentworth,  GK  A.  and  Hill,  G.  A.  A  Text-book  of  Physics.  Boston, 
Ginn  &  Co.  1898.  Pp.  440. 

Wright,  M.  B.  Elementary  Physics  for  the  Use  of  Schools  and  Col- 
leges. London  and  New  York,  Longmans,  Green  &  Co.  Pp.  256. 

WE  have  now  considered  the  natural  qualifications  of  a 
teacher  of  physics,  his  formal  professional  education  and  some 
of  the  means  and  habits  by  which  he  can  keep  himself  a  student 
and  a  thinker  during  the  routine  practice  of  his  profession.  It 
is  now  time  for  us  to  consider  what  should  be  his  general 
method  or  theory  of  teaching. 

If  I  had  undertaken  to  write  on  this  subject  twenty  years  ago, 
it  is  doubtful  whether  I  should  have  said  anything  about  labora-  / 
tory  work  for  the  pupils  in  general  of  secondary  schools.     Noi 

such  work  was   provided  for  by  the  text-books  in 
Retrospect. 

common  use  at  that  time  ;  and  the  school-teachers 

of  physics,  who,  as  a  rule,  had  never  enjoyed  laboratory  oppor- 
tunities for  the  study  of  the  science,  and  who  often  were  mere 
conscripts  in  the  service  of  physics  teaching,  were  not  much  in 
the  habit  of  extending  their  activity  beyond  the  reach  and  direc- 
tions of  the  book  in  hand. 

Fifteen  years  ago   I  should  have  had  to  consider  the  ques-  \ 
tion,  strictly  a  question   at  that  time,  whether  class  laboratory  » 
work  in  the  school  teaching  of   physics  is  practicable  or  de- 
sirable.    To-day  the   question  is,  What  laboratory  work  shall    ' 
be  done,  how  much,  and  in  what  spirit?     Practically,  all  the 
American  physics  text-books  written  for  use  in  secondary  schools  . 
nowadays  take  class  laboratory  work  for  granted,  although  they 
differ  among  themselves  in  the  amount  and  character,  or  motive, 
of  the  exercises  which  they  recommend. 

The  main  purpose  of  the  text-books  twenty  years  ago  was  to 
give  information.  Training  of  the  senses  and  of  the  powers  of 
General  Infer-  observation  and  reflection  was  hardly  considered  in 
mation.  Type  their  construction.  They  had  little  more  care  than 
dictionaries  have  for  the  intellectual  processes  of 
their  readers.  In  their  one  function  they  probably  were,  when 
faithfully  studied,  fairly  successful.  For  example,  Arnott's  Ele- 


SCHOOL    TEXT-BOOKS  OF  PHYSICS          269 

ments  of  Physics,  1877,  recommended  to  schools  by  Harvard 
University  in  1881,  contained  a  vast  number  of  interesting  state- 
ments, most  of  which  would  still  be  accepted  as  true.  It  had 
8  73  pages,  and,  though  it  was  without  an  index,  its  table  of  con- 
tents covered  13  pages.  It  dealt  with  an  enormous  variety  of 
particulars.  But  it  did  not,  I  believe,  give  one  problem  of  any 
kind  for  solution  by  the  reader.  In  fact,  I  doubt  whether  there 
was  in  the  whole  book  a  single  interrogation,  except  those  of  a 
rhetorical  character.  The  object  and  hope  of  the  book  seemed 
to  be,  so  fully  to  anticipate  all  needs  and  questions  of  the  reader 
that  he  would  never  have  to  do  any  thinking  on  matters  of 
physics. 

Of  course,  this  book  was  the  extreme  of  its  type,  and  for  that 
reason  I  have  described  it,  my  object  being  not  so  much  to  show 
how  great  the  change  has  been  in  twenty  years,  as  to  make  plain 
what  manner  of  book  results  from  the  complete  neglect  of  the 
training  function.  In  spite  of  the  fact  that  many  a  middle- 
aged  man  remembers  such  books  with  a  kind  of  fondness,  and 
loyally  declares  his  indebtedness  to  them,  a  general  recognition 
of  their  superficial  and  unsatisfactory  character  has  gradually 
retired  them  from  use.  Books  appealing  more  to  the  reason  of 
the  pupil,  treating  him  as  a  growing  thing,  to  be  fed,  developed, 
and  trained,  rather  than  as  a  receptacle  to  be  filled,  have  taken 
their  place. 

It  is  not  in  physics  alone,  or  in  natural  science  alone,  that  a 
change   like  this  has  occurred.     A  general  movement  of  the 
same  kind  was  characteristic  of  the  latter  part  of  the 
nineteenth  century  in  all  fields  of  educational  ac-  change  of 

tivitv  in  America.     One  of  the  first  text-books  of  View  and 

Method. 
physics,  if  not  the  very  first,  to  show  this  movement 

was  the  Elements  of  Physics,  written  by  Mr.  A.  P.  Gage  of  the 
Boston  English  High  School,  which  appeared  in  1882.  This 
book  carried  on  its  cover  the  exhortation,  "  Read  Nature  in  the 
Language  of  Experiment,"  and  it  described  many  experiments 
to  be  performed  by  the  pupils.  The  Author's  Preface  began 
thus:  "In  his  report  for  the  year  1881,  Mr.  E.  P.  Seaver, 


270         SCHOOL    TEXT-BOOKS  OF  PHYSICS 

Superintendent  of  the  Public  Schools  of  Boston,  says  :  l  It  is 
a  cardinal  principle  in  modern  pedagogy  that  the  mind  gains  a 
real  and  adequate  knowledge  of  things  only  in  the  presence  of 
the  things  themselves.  Hence,  the  first  step  in  all  good  teach- 
ing is  an  appeal  to  the  observing  powers/  "  etc.  That  is,  labo- 
ratory work,  the  laboratory  method  of  study  for  pupils  of  the  high 
school  age,  was  in  the  air,  so  much  so  that  its  most  enthusiastic 
advocates  did  not  trouble  themselves  to  argue  for  the  desirability, 
but  only  for  practicability,  of  such  a  feature  in  the  school  course. 

Gage's  book  soon  came  into  wide  use,  and  it  must  have  ex- 
erted a  great  influence  on  the  methods  of  instruction  in  physics 
in  the  United  States.  Meanwhile  there  were  other  much-used 
text-books,  good  in  their  way,  which  I  do  not  mention  here  by 
name,  because  they  were  not  particularly  influential  in  pushing 
forward  that  revolution  of  practice  the  course  of  which  I  am 
roughly  tracing. 

An  act  of  importance  in  this  history  was  the  publication,  in 
1886,  of  the  following  statement,  as  a  definition  of  one  of  the 
alternative  requirements  in  physical  science  for  ad- 
Action  on  mission  to  Harvard  College  :  "  A  course  of  experi- 

Physics  for  ments  in  the  subjects  of  mechanics,  sound,  light, 
Admission. 

heat,  and  electricity,  not  less  than  forty  in  number, 

actually  performed  at  school  by  the  pupil.  These  experiments 
may  be  selected  from  A.  M.  Worthington's  Physical  Laboratory 
Practice  (Rivingstons,  London,  1886),  or  from  the  New 
Physics,  by  John  Trowbridge  (Appleton  &  Co.,  New  York), 
or  from  any  similar  laboratory  manual."  This  was  supplemented 
by  the  further  statements,  "  In  the  second  of  the  alternatives  in 
elementary  physics,  .  .  .  the  candidate  will  be  required  to  pass 
both  a  written  and  a  laboratory  examination.  The  written  ex- 
amination will  be  directed  to  testing  the  candidate's  knowledge 
of  experiments  and  experimenting,  as  well  as  his  knowledge  of 
the  principles  and  results"  of  the  science.  "The  laboratory 
examination  will  be  directed  to  testing  his  skill  in  experimenting. 
At  the  hour  of  the  written  examination  the  candidate  will  be 
required  to  hand  in  the  original  note-book  in  which  he  recorded 


SCHOOL    TEXT-BOOKS  OF  PHYSICS         2JI 

the  steps  and  results  of  the  experiments  which  he  performed  at 
school,"  etc.  "  Most  pupils  will  need  lectures  or  other  oral  ex- 
planations in  addition  to  the  descriptions  given  in  the  laboratory 
manuals.  When  it  is  impossible  to  provide  lectures,  an  addi- 
tional text-book  made  from  a  different  standpoint  will  be  found 
of  advantage." 

From  Arnott's  Physics  (Harvard  Requirements,  1881)  to  this 
statement  is  a  very  wide  swing  of  the  educational  pendulum,  — 
too  wide,  indeed.  Chemists  were  more  influential  change  Too 
than  physicists  in  framing  the  new  science  require-  Great- 
ments,  and  they  made  the  mistake  of  treating  the  physics  just  as 
they  treated  the  chemistry.  The  emphasis  was  all  put  on  "  ex- 
periments and  experimenting,"  the  other  work  of  the  proposed 
requirement  being  mentioned  later  and  almost  incidentally. 
The  written  examination  was  to  be  directed  in  part  to  experi- 
ments and  experimenting,  while  the  laboratory  examination  must 
be  devoted  exclusively  to  experimenting.  Undoubtedly  this  was 
too  great  a  reaction  from  the  methods  of  the  preceding  decade. 

The  latitude  of  choice,  in  laboratory  work,  permitted  by  the 
letter  of  the  new  requirement,  forty  experiments  chosen  at  will 

from  either  of  two  very  unlike  manuals,  "  or  from 

,  Influence  of 

any  similar  laboratory  manual,  made  it  neces-  Harvard 
sary  for  the  College  to  get  out  a  Descriptive  '^e^riptive, 
List  of  acceptable  experiments,  that  is,  a  pam- 
phlet giving  detailed  directions  for  the  performance  of  the  pre- 
scribed number  of  laboratory  exercises.  This  List  soon  came 
into  very  common  use  within  the  especial  sphere  of  Harvard 
influence,  and  presently  a  number  of  text-books  appeared-which 
were  prompted,  directly  or  indirectly,  by  the  course  of  labora- 
tory work  laid  down  in  this  pamphlet.  These  books,  though 
differing  considerably  among  themselves,  constituted  a  strongly 
marked  type,  almost  the  antipodes  of  the  Arnott's  Elements, 
which  had  not  long  preceded  them. 

But  some  years  of  use  brought  to  general  recognition  the 
already  noted  defect  of  the  Harvard  requirement,  and  of  the 
text-books  corresponding  to  it,  the  over-emphasis  on  exacting 


2/2          SCHOOL    TEXT-BOOKS  OF  PHYSICS 

laboratory  work,  and  the  consequent  lack  of  opportunity  for 
sufficiently  varied  instruction.     Accordingly,  in  1897,  the  Har- 
vard Catalogue  gave  a  new  statement  of  the  re- 
A  Revision. 

quirement  in  Elementary  Physics,  from  which  state- 
ment the  following  extracts  are  taken  :  "  Elementary  Physics, 
—  A  course  of  study  dealing  with  the  leading  elementary 
facts  and  principles  of  physics,  with  quantitative  laboratory 
work  by  the  pupil. 

"  The  instruction  given  in  this  course  should  include  qualita- 
tive lecture-room  experiments,  and  should  direct  especial  atten- 
tion to  the  illustrations  and  applications  of  physical  laws  to  be 
found  in  every-day  life." 

"The  pupil's  laboratory  work  should  give  practice  in  the 
observation  and  explanation  of  physical  phenomena,  some  fa- 
miliarity with  methods  of  measurement,  and  some  training  of 
the  hand  and  the  eye  in  the  direction  of  precision  and  skill.  It 
should  also  be  regarded  as  a  means  of  fixing  in  the  mind  of  the 
pupil  a  considerable  variety  of  facts  and  principles." 

The  Descriptive  List  was  re-written  to  fit  the  new  require- 
ment. But  such  text-books  as  have  been  written  with  especial 
reference  to  this  List,  even  in  its  revised  form,  continue  to  be 
a  rather  marked  type,  distinguished  by  their  great  attention  to 
laboratory  work,  by  their  detailed  description  of  such  work,  and 
by  the  intimate  relation  which  they  maintain  between  it  and 
work  of  other  kinds. 

In  most  parts  of  the  country  the  change  to  laboratory  methods 
of  instruction  was  less  rapid  and  less  sweeping  than  in  those 

places  where  the  influence  of  Harvard  was  pre- 
Otner  Inliu-  f  l 

ences.  Ann  dominant ;  but  a  movement  of  the  same  general 
character  has  been  widespread,  many  teachers  in 
many  places  helping  it  on,  each  in  his  own  way.  Ann  Arbor, 
through  the  books  written  by  men  connected  with  her  educa- 
tional institutions,  early  became  and  has  remained  a  centre  of 
great  influence. 

It  is  quite  probable,  however,  that,  even  to  the  present  time, 
the  most  successful  text-books,  from  the  point  of  view  of  numbers 


SCHOOL    TEXT-BOOKS  OF  PHYSICS         273 

sold,  have  been  those  making  little  of  laboratory  work,  follow- 
ing, rather  than  leading,  the  change  of  opinion  and  practice. 
Books  still  appear  in  which  the  treatment  of  labo-  conservative 
ratory  work  seems  rather  perfunctory.  It  must  be  ^wika' 
said  in  favour  of  such  books  that  for  cyclopaedic  purposes  or  any 
hasty  use  they  are  more  convenient  than  those  in  which  the 
laboratory  work  is  more  prominent  and  more  closely  amalga- 
mated with  the  other  parts. 

The  ideal  text-book,  which  is  to  satisfy  all  kinds  of  teachers 
and  all  kinds  of  schools  and  sweep  all  competitors  from  the 
field,  has,  apparently,  not  yet  appeared,  in  spite  of  NoAiiSuffi- 
the  many  efforts  which  are  constantly  being  made  cientBook. 
to  produce  it.  There  seems  to  be,  for  the  young  teacher,  no 
escape,  at  present,  from  the  task  of  studying  the  conditions  of 
his  own  school,  studying  the  characteristics  of  a  number  of 
text-books,  and  then  making  his  choice  according  to  his  own 
best  judgment,  choosing  more  than  one  book  if  this  is  practi- 
cable. In  a  few  years  he  will  be  writing  a  book  of  his  own, 
which  may  prove  to  be  the  book. 

In  the  next  chapter  I  shall  discuss  and  illustrate  various 
theories,  or  views,  of  laboratory  work  which  appear  to  have 
guided  the  authors  of  current  school  text-books  of  physics. 


18 


CHAPTER  VI 

DISCOVERY,   VERIFICATION,    OR   INQUIRY? 

REFERENCES. 

Armstrong,  W.  E.  The  Heuristic1  Method  of  Teaching.  Vol.  2  of 
Special  Reports  on  Educational  Subjects.  Department  of  Education  of 
the  English  Government.  Pp.  389-413. 

Cajori.  The  Pedagogic  Value  of  the  History  of  Physics.  SCHOOL 
REVIEW.  May,  1899.  Pp.  278-285. 

Fouillee,  A.  Education  From  a  National  Standpoint.  London, 
E.Arnold.  New  York,  D.  Appleton  &  Co.  1892.  Pp.332.  Chap.  II. 
MacGregor,  J.  Q.  Knowledge-Making.  NATURE.  Dec.  14,  1899. 

The  Prefaces  of  all  American  school-books  of  physics  published  during 
the  last  ten  years. 

YEARS  ago,  when  I  was  a  novice  in  the  laying  out  x)f  a  course 
of  physics  for  schools,  an  eminent  professor  declared  to  me 
"  ind  ctive "  w^  much  impressiveness,  "  There  are  two  ways  of 
and"Deduc-  teaching  science,  the  inductive  method  and  the 
deductive  method.  The  inductive  method  is  the 
only  one  that  has  any  business  in  the  schools."  Another,  still 
more  eminent,  authority,  when  in  his  presence  I  happened  to 
use  the  phrase,  "  the  verification  of  Boyle's  law,"  exclaimed  with 
emphasis,  "That  is  the  very  attitude  we  want  to  avoid,  the 
attitude  of  verification." 

In  the  light  of  all  my  observation  and  experience,  I  am  now 
of  the  opinion  that  the  first  maxim  was  a  very  bad  one,  and  the 
second  a  very  good  one.  The  first  is  a  harmful  exaggeration 
of  the  truth  of  the  second. 

It  is  certainly  unwise  to  take  the  position  that  the  pupil  must 
be  brought  to  the  acceptance  of  every  truth  by  the  roundabout 

1  See  also  the  last  chapter  of  this  book. 


DISCOVERY,    VERIFICATION,    OR  INQUIRY     2?$ 

«% 

method  of  proceeding  from  axioms  along  a  continuous  chain  of 
demonstration,  which  he  must  put  together  link  by  link.  It  is 
well  to  follow  this  course  in  geometry ;  it  is  well  to  follow  it 
often  in  physics,  partly  for  the  mental  training  it  gives,  and  partly 
for  the  light  it  throws  on  the  methods  by  which  others  have 
sought  out  the  truths  of  the  science ;  but  it  is  absurd  to  say 
that  the  young  pupil  should  be  permitted  to  take  nothing  at 
second-hand.  Youth  is  too  short,  and  life  is  too  short,  for  such 
a  doctrine. 

It  is  probable,  indeed,  that  no  teacher  and  no  writer  of  text- 
books would  profess  to  hold  this  doctrine  without  limitations. 
But,  nevertheless,  the  "inductive  method,"  or  the  Ajnigesof 
method  of  discovery,  is  often  overworked,  with  the   Inductive 
result  that  it  must  break  down  or  be  continued  as 
a  mere  pretence,  most  harmful  to  the  intellectual  morals  of 
all  who  are   parties  to  it. 

For  example,  it  is  well,  of  course,  to  encourage  and  require 
the  pupil  to  put  down  at  the  end  of  an  experiment  what  he  has 
got  out  of  it ;  but  it  has  often  seemed  to  me  that  the  printed 
order  to  "  infer,"  which  is  given  at  the  end  of  each  exercise  in 
some  of  the  ruled  and  formulated  note-books  now  so  much 
used,  is  often  too  large  for  the  occasion  and  leads  the  pupil  to 
put  down  some  unqualified  law,  not  justified  by  the  evidence 
which  he  presents,  or  to  venture  some  platitudinous  remark 
where  the  only  real  inference  is  a  numerical  result. 

If  my  memory  is  not  playing  me  false,  I  once  saw  directions 
for  an  experiment  in  which  the  pupil  was  to  watch  intently  for 
some  time  a  bit  of  wood  lying  on  a  table,  and  then,  after  re- 
flection, to  write  down  the  inference,  Matter  cannot  set  itself 
in  motion.  This  experiment  was  very  consistently  followed  by 
another,  in  which  the  pupil,  after  poking  the  object  and  duly 
reflecting,  was  expected  to  write  down  the  inference,  Matter 
can  be  set  in  motion  by  force.  I  remember  another  book  of 
experiments,  to  be  used  at  home  by  young  boys,  which  began 
by  the  dropping  of  a  stone  into  a  vessel  filled  with  water,  and 
developed  the  subject  and  the  pupils  so  rapidly  as  to  ask 


276      DISCOVERY,    VERIFICATION,    OR  INQUIRY 

0 

the  latter,  on  the  second  page,  whether,  in  their  opinion, 
according  to  Experiment  4,  sunlight  is  matter. 

Such  is  the  method  of  discovery  at  its  worst.  It  would  be 
unfortunate  for  young  pupils  to  get  the  notion  that  science 
has  been  developed  by  such  methods  of  observation  and  in- 
ference as  those  just  indicated. 

But  what  of  this  method  at  its  best  ?  Doubtless  at  its  best  it 
works  very  well ;  but  what  are  the  conditions  necessary  for  this 
The  Method  success?  A  very  competent  teacher,  who  knows 
at  its  Best.  tjie  gr0und  thoroughly,  and  will 'not  delude  him- 
self or  his  pupils  with  exaggerated  notions  of  their  independ- 
ence and  originality  in  science,  and  a  very  small  class.  The 
method,  sometimes  advocated,  of  teaching  children  to  swim  by 
throwing  them  into  deep  water,  will  surely  be  fatal  to  a  very 
large  proportion  of  the  unhappy  youngsters,  unless  there  is 
some  experienced  person  with  every  group  of  three  or  four. 
For  a  single  pupil  in  the  art  of  swimming  a  judicious  teacher 
is  better  than  a  life-preserver ;  but,  if  the  teacher  must  have 
fifteen  or  twenty  beginners  in  charge  at  once,  in  the  name  of 
humanity  let  him  give  them  something  to  float  with,  or  keep 
them  very  near  the  shore.  Usually,  I  am  sure,  the  teacher  who 
thinks  to  let  his  pupils  "  find  out  everything  for  themselves  " 
will  find  out  for  himself  that  he  has  somehow  got  the  hardest 
part  of  the  undertaking.  For  visible  progress  must  be  made, 
tangible  results  must  be  reached ;  the  teacher  must  somehow 
bring  things  to  pass,  in  spite  of  the  vast  capacity  for  going 
wrong  which  marks  the  efforts  of  the  ordinary  individual,  as 
it  has  marked  the  efforts  of  the  human  race,  to  "  find  things 
out." 

Young  people  are  not  averse  to  games  of  hunting ;  but,  if  the 
hunting  lasts  very  long  without  result,  most  of  the  participants 
Art  of  Dis-  wiM  fell  out>  an°l  tne  game,  m  school  or  out,  will  flag. 

covering  Gen-  Most  general  laws  or  relations  in  physics  are  too 
era!  Laws 

cannot  t>e  difficult  for  the  pupil  to  seek  out.     Even  when   all 

Taught.  tjie  necessary  (}ata  are  at   hand,  the    unprompted 

recognition,  the  genuine  discovery,  of  the  resultant  law  is  either 


DISCOVERY,    VERIFICATION,    OR  INQUIRY     277 

an  accident  or  an  inspiration  akin  to  accident  The  art  of  such 
discovery  cannot  be  taught.  But  physics  is  peculiar  among  the 
natural  sciences  in  presenting  in  its  quantitative  aspect  a  large 
number  of  perfectly  definite,  comparatively  simple,  problems, 
not  beyond  the  understanding  or  physical  capacity  of  young 
pupils.  With  such  problems  the  method  of  discovery  can  be 
followed  sincerely  and  profitably. 

Let  us  now  consider  the  method  of  verification.  It  is  hard 
to  imagine  any  disposition  of  mind  less  scientific  than  that  of 
one  who  undertakes  an  experiment  knowing  the  Method  of 
result  to  be  expected  from  it  and  prepared  to  look  Verification. 
so  long,  and  only  so  long,  as  may  be  necessary  to  attain  this 
result.  Better  by  far  to  take  a  statement  on  faith  than  to  culti- 
vate the  habit  of  hunting  for  evidence  in  its  favour  and  shutting 
one's  eyes  to  inconvenient  evidence  against  it.  A  trait  that  has 
characterized  the  great  masters  of  science  has  been  the  power 
and  habit  of  sternly  searching  the  evidence  for,  as  well  as  the 
evidence  against,  their  own  propositions. 

The  suggestion  that  pupils  whose  minds  are  prejudiced  in 
favour  of  a  certain  belief  will  pervert  the  evidence  of  their  own 
senses  is  sometimes  ridiculed  or  resented ;  but,  unfortunately, 
I  have  seen  too  many  instances  of  such  perversion  pre:udice 

to  doubt  its  prevalence.    It  is  sometimes  conscious,   Perverts 
^  ,  ...    Evidence, 

sometimes  unconscious.     Even  when  conscious,  it 

is  frequently  quite  open  and  without  sense  of  wrong-doing. 
"  Why  should  I  put  down  an  observation  which  I  know  can't  be 
right?"  the  boy  will  ask  in  perfect  innocence. 

Of  course,  there  are  cases  in  which  the  conditions  of  a  par- 
ticular observation  are  such  as  to  make  it  peculiarly  uncer- 
tain, —  much  more  uncertain  than  the  other  observations  which 
would  naturally  be  grouped  with  it,  —  and  in  cases  like  this  the 
observation  in  question  should  be  rejected,  even  if  it  happens 
to  agree  with  our  preconceived  notion  of  what  it  should  be. 
But  when  all  the  observations  of  the  same  sort  have  been  made 
under  equally  good  conditions,  so  far  as  these  conditions  are 
known,  we  must  not  reject  some  of  them  because  they  do  not 


2/3      DISCOVERY,    VERIFICATION,    OR  INQUIRY 

agree  with  the  others,  or  because  they  do  not  agree  with  our 
notions  of  what  they  ought  to  be.  Yet  I  have  again  and  again 
found  the  tendency  to  do  just  this  thing,  and  not  always  among 
pupils  only. 

There  is  very  little  to  choose  between  the  method  of  verifica- 
tion at  its  worst  and  the  pseudo  method  of  discovery.  The 
former  says  to  the  pupil,  The  fact  is  so  and  so  ;  make  observa- 
tions accordingly.  The  latter  says,  Make  observations;  from 
these  discover  the  fact,  which  is  so  and  so.  We  need  something 
better  than  either  of  these  methods  to  justify  the  expense  and 
work  of  laboratory  courses. 

I  would  keep  the  pupil  just  enough  in  the  dark  as  to  the 
probable  outcome  of  his  experiment,  just  enough  in  the  attitude 
of  discovery,  to  leave  him  unprejudiced  in  his  observations, 
and  then  I  would  insist  that  his  inferences,  so  far  as  they  pro- 
Method  of  fess  to  be  derived  from  his  own  seeing,  must  agree 
Inquiry.  with  ^}ie  record,  previously  made  and  unalterable,1 
of  these  observations.  The  work  may  relate  to  some  single 
phenomenon,  fact,  or  constant,  or  to  some  general  law ;  but  in 
any  case  the  experimenter  should  hold  himself  in  the  attitude 
of  genuine  inquiry. 

This  attitude  is  not  necessarily  inconsistent  with  fore-knowl- 
edge of  what  the  result  sought  should  be  according  to  the 
Spirit  of  the  testimony  of  books.  Much  depends  on  the  spirit 
Teaching.  of  the  teaching.  If  this  is  such  as  to  show  that  no 
forcing  or  perversion  of  observations,  no  pretence  in  the  reason- 
ing from  these  observations,  will  be  tolerated,  if  known,  the 
pupils  are  likely  to  be  powerfully  affected  by  it.  But  if  the  text- 
book used  is  one  that  emphatically  states  laws  or  quantities,  and 
then  instructs  the  pupil  to  "  verify  "  these  laws  or  quantities  in 
the  laboratory  exercises,  it  will  require  strong  counter-instruc- 
tion from  the  teacher  to  make  these  exercises  proceed  in  the 


1  Sometimes  an  inspection  of  the  observations  will  disclose  a  perfectly 
obvious  blunder,  such  as  a  mistake  of  ten  degrees  in  reading  a  thermom- 
eter. Of  course  in  such  cases  the  record  should  be  amended,  with  a 
note  describing  the  change. 


DISCOVERY,    VERIFICATION,   OR  INQUIRY     2J$ 

right  spirit.     It  is  better  to  keep  young  observers  out  of  tempta- 
tion until  they  are  accustomed  to  depend  on  themselves. 

Consider,   for  example,    the  law    of  Boyle    regarding  gases.  • 
This  law  is  very  important,  and  the  manipulation  of  the  appara-  ' 

tus  illustrating  it  is  excellent  practice  for  the  pupil. 

.      .        a  .     ,,  .       .       .         ...     Illustrations. 

But  the  law  is  numerically  so  very  simple  that,  if  it 

were  clearly  in  the  minds  of  the  class  before  the  experiment, 
and  especially  if  the  order  to  "  verify  "  the  law  had  been  issued, 
some  in  any  large  class  would  be  pretty  sure  to  feel  their  way 
along,  making  calculations  in  advance  of  records,  leaving  out 
undesired  millimeters,  and  attain  a  result  in  beautiful  accord 
with  the  idea  which  inspired  them,  but  probably  not  quite  in 
accord  with  the  evidence  of  the  apparatus  and  their  own  unper- 
verted  senses.  On  the  other  hand,  the  parallelogram  of  forces 
is  a  law  so  complicated  that  it  is  difficult  for  the  pupil,  when  he 
is  making  his  observations  on  the  magnitude  and  directions  of 
the  three  balanced  forces,  to  see  whether  these  observations 
will  or  will  not  lead  to  a  perfect  parallelogram,  and  there  is  no  \ 
harm  in  letting  him  know,  in  advance,  just  what  the  law  is,  pro- 
vided there  is  some  adequate  control  and  check  on  the  use  of 
these  observations.1  The  object  of  the  experiment  in  this  case 
is  to  make  the  pupil  realize  the  meaning  of  the  law,  while  giving 
him  an  opportunity  to  exercise,  and  by  the  final  result  to  test, 
his  skill. 

The   teacher  and  the  pupils   should  know  that  various  so- 
called  laws  are  not  strictly  true  and  that  even  elementary  labo- 
ratory work  may  go  far  enough  to  show  their  falli-  Imccnra     of 
bility.     For  example,  according  to  my  observation   Some 
of  wooden  blocks  sliding   on  a    surface  of  paper,     '   aws' 
friction  is  not  independent  of  velocity,  but  is  a  little  greater  at 
high  speed  than  at  low,  a  conclusion  contrary  to  what  I  should 


1  My  practice  is  to  have  the  pupil  make  his  observations,  that  is,  draw 
his  lines  and  record  his  readings,  on  a  sheet  of  paper  placed  beneath  the 
strings  through  which  the  forces  are  applied,  and  then,  with  a  pin,  prick 
through  the  significant  parts  of  his  diagram  into  a  sheet  of  paper  beneath, 
which  sheet  remains  in  the  laboratory  as  a  copy  of  the  record. 


280      DISCOVERY,    VERIFICATION,   OR  INQUIRY 

have  expected.  The  difference  is  so  slight,  however,  that  a 
boy  who  has  been  told,  as  boys  are  sometimes  told  in  advance 
of  experiment,  that  there  is  no  such  difference,  is  pretty  sure 
not  to  find  it,  and  that  very  promptly.  A  good  practice  in 
such  a  case  is  to  tell  the  class  that  the  difference,  or  depar- 
ture from  the  so-called  law,  if  there  is  any,  is  slight,  and  that, 
after  each  pupil  has  tried  the  experiment  and  recorded  his 
unbiased  judgment,  the  opinion  of  the  majority  will  be  taken 
and  announced.  The  fact  of  the  inequality  noted  in  such  a 
case  as  this  may  not  be  important,  but  the  power  and  habit  of 
seeing  what  there  is  to  see,  and  not  merely  what  one  is  told  to 
see,  is  important. 

Another  instance  in  which  class  observation  brings  out  an 
interesting  fact  which  the  experiment  was  hardly  expected 
to  reveal,  is  found  in  the  exercise  on  the  position  of  the 
image  formed  by  a  plane  mirror.  In  writing  the  directions 
for  such  an  exercise  I  had  made  no  mention  of  the  need 
of  making  some  allowance  for  the  refraction  by  the  glass, 
which  virtually  brings  the  reflecting  back  surface  of  the  mirror 
a  little  forward  from  the  straight  line  over  which  it  is  care- 
fully placed.  Examining  the  work  of  pupils,  however,  I 
have  found  that  this  refraction  does  produce  a  plainly  per- 
ceptible effect  in  many  cases.  If  nearly  perpendicular  in- 
cidence and  reflection  were  used,  this  virtual  moving  forward 
would  be  equal,  nearly,  to  one-third  the  thickness  of  the 
glass;  but,  as  the  incidence  used  is  generally  very  oblique, 
the  virtual  reflecting  surface,  as  found  by  the  point  of  crossing 
of  the  lines  of  incidence  and  reflection,  may  be  nearer  to 
the  front  surface  than  to  the  back  surface  of  the  mirror.  It 
would  be  unfortunate  to  blink  out  of  sight  a  fact  like  this,  even 
though  its  complete  discussion  may  have  to  be  postponed  for 
a  time. 

I  have  already  alluded  to  cases  in  which  the  laws  to  be  illus- 
trated or  revealed  by  the  experiment  are  of  such  a  nature  that 
the  work  of  no  one  pupil  is  sufficient  for  the  general  purpose, 
and  combination  or  comparison  of  results  becomes  necessary 


DISCOVERY,    VERIFICATION,   OR  INQUIRY     281 

One  of  the  best  illustrations  of  this  class  of  exercises  is  fur- 
nished by  experiments  on  the  deflection  of  rods  of  various 
dimensions.  My  habit  in  dealing  with  this  matter  Pooling  of 
is  the  following  :  Each  member  of  the  class  has  at  Observations. 
his  command  two  white  pine  rods,  as  nearly  alike  in  grain  as  may 
well  be,  each  a  little  more  than  a  meter  long,  one  being  i  cm. 
square  in  cross-section,  the  other  2  crn.  by  i  cm.  Each  rod  is 
studied  under  various  loads,  and  for  each  rod  and  each  condi- 
tion of  trial  the  mean  deflection  per  i-gm.  load  is  found  and 
reported  by  the  student  to  whom  that  particular  mustration . 

rod   is  assigned.     The   results   are   then   grouped  Laws  of 

Bending, 
under  headings  as  follows  : 

ist  Case,  rod  no.  i  (i  cm.  square),  supports  100  cm. 
apart. 

zd  Case,  rod  no.  i,  supports  50  cm.  apart. 

$d  Case,  rod  no.  2  (2  cm.  by  i  cm.)  on  broad  side,  supports 
100  cm.  apart. 

tfh  Case,  rod  no.  2  on  edge,  supports  100  cm.  apart. 

The  results  found  for  any  one  case  by  different  members  of 
the  class  will  differ  greatly,  partly  because  the  various  rods  differ 
somewhat  in  quality  and,  very  slightly,  in  dimensions,  partly 
because  the  work  of  observation  is  not  first-rate,  partly  because 
of  numerical  errors  in  the  computations.  Some  reports  are  so 
wild,  from  evident  misapprehension  of  the  problem,  or  from 
gross  numerical  errors,  like  misplacement  of  the  decimal  point, 
that  they  must  be  rejected  ;  but  it  will  be  seen  from  the  numbers 
given  below  that  a  very  liberal  standard  of  admissibility  is 
applied,  and  that  the  range  of  numerical  values  grouped  together 
is  large.  Nevertheless,  and  this  is  a  very  instructive  lesson  to 
students,  general  results  of  considerable  accuracy  can  be  worked 
out  from  a  great  mass  of  individually  inaccurate  data,  provided 
the  inaccuracies  are  of  the  accidental  sort,  so  that  errors  in  one 
direction  may,  in  the  general  average,  be  eliminated,  or  offset, 
by  errors  in  the  opposite  direction. 


282      DISCOVERY,    VERIFICATION,   OR  INQUIRY 


DEFLECTIONS    PER   ONE   GRAM   OF   LOAD. 


ist  Case. 

2d  Case. 

0.000915  cm. 

800 

O.OOOII5  cm. 

1090 

140 

1090 

140 

957 

129 

1050 

I36 

1010 

I  •?  c 

884 

103 

895 

120 

920 

1  2O 

951 

124 

914 

IO9 

I22O 

r35 

870 

1  20 

IO5O 

US 

II5O 

1  60 

950 

147 

II7O 

140 

II4O 

153 

1330 

130 

3d  Case. 

4th  Case. 

0.000620  cm. 

0.000135  cm. 

434 

109 

725 

I23 

700 

I23 

587 

130 

418 

III 

465 

125 

47° 

116 

463 

120 

445 

120 

597 

143 

502 

I29 

505 

1  2O 

520 

I4O 

450 

120 

420 

IO5 

596 

132 

435 

1  08 

463 

123 

426 

1  1  1 

Mean  0.001018  cm.          0.000130  cm.          0.000512  cm.  0.000122  cm. 

In  comparing  case  i  with  case  2  we  get  the  effect  of  doub- 
ling the  length,  other  things  being  equal.  We  see  at  once  that 
Search  for  deflection  increases  with  increase  of  length  ;  but  is 
the  Laws.  deflection  proportional  to  length  ?  Is  the  rule 
D  oc  L  ?  Evidently  not ;  the  deflection  increases  in  far  greater 
proportion  than  the  length. 

Is  the  rule  D  oc  L2?  This  would  require  the  deflection  of 
the  ist  case  to  be  only  four  times  that  of  the  2d  case,  and  it 
is  more  than  that. 

Is  the  rule  D  oc  L8  ?  This  would  require  the  first  deflection 
to  be  8  times  the  second.  In  fact,  it  is  7.8  times  the  2d.  This 
is  very  fair  agreement,  and  shows  that  the  formula  last  written 
comes  pretty  near,  at  least,  expressing  the  experimental  facts 
of  the  case.  That  is  all  we  can  claim  for  the  testimony, 
that  it  points  to  the  law  D  oc  L3,  which  more  careful  and 
extensive  experiments  by  others  have  shown  to  be  very  nearly 
correct. 

A  comparison  of  cases  i  and  3  shows  the  effect  of  doubling 


DISCOVERY,    VERIFICATION,    OR  INQUIRY     283 

the  width,  other  things  remaining  unchanged.  The  ratio  of 
deflection  i  to  deflection  3  is  1.99,  indicating  the  otherwise 
known  law  D  oc  i  /  W. 

Comparison  of  cases  i  and  4  shows  the  effect  of  doubling 
the  thickness,  other  things  remaining  unchanged.  The  ratio 
of  deflection  i  to  deflection  4  is  8.34,  which  is  in  tolerable 
accord  with  the  accepted  law  D  oc  i  /  T3. 

Grouping  these  various  proportions  into  one  general  formula, 
and  introducing  also  the  already  known  rule  D  oc  P,  where  P 
is  the  load,  we  get 

P  X  L3 


This  derivation  of  formulas  I  do  not  expect  the  students 
to  carry  through  by  themselves  ;  for,  as  a  rule,  no  one  student 
has  from  his  own  observations  sufficiently  reliable  data  to  make 
the  whole  discussion  satisfactory,  and,  moreover,  the  ordinary 
student  could  not  reasonably  be  expected  to  conduct  such  a 
discussion  without  assistance.  I  put  the  tabulated  individual 
results  on  the  blackboard,  and  go  through,  in  a  lecture,  the 
course  of  reasoning  indicated  by  what  has  just  been  given. 
The  numbers  shown  above  were  reported  by  twenty  members 
of  a  class  in  the  year  1900-1901,  and  were  used  by  me  in  class 
substantially  as  I  have  used  them  here. 

The  comparison  of  masses  by  the  acceleration  test  is  another 
case  in  which,  owing  to  experimental  difficulties,  a  general 
aggregation  of  results  is  desirable.  In  this  exercise 


two  cars,  one  loaded  with  iron,  the  other  with  lead,  lustration  of 
are  set  in  motion  by  the  equal  pulls  of  like  tubes  of 
india-rubber,  equally  stretched,  along  inclines  so  adjusted  as  to 
neutralize   friction.     When   apparent   equality   of  acceleration 
has  been  attained,  by  varying  one  or  the  other  load,  the  cars, 
each  with  its  contents,  are  separately  weighed.      Students  work 
in  groups,  usually  of  three,  in  this  undertaking,  and  record,  as 
their  results,  the  weighings.     In  1900-1901  twenty  such  groups 
reported  the  following  numbers  : 


284      DISCOVERY,    VERIFICATION,    OR  INQUIRY 


ist  Case. 

2d  Case. 

3d  Case. 

With  Iron. 

With  Lead. 

With  Iron. 

With  Lead. 

With  Iron. 

With  Lead. 

1460 

1410 

1240 

1255 

IOIO 

1050 

1500 

1490 

1270 

1290 

1040 

1090 

1500 

!590 

1370 

1330 

1160 

1170 

1490 

1450 

1260 

1240 

IO4O 

1030 

1480 

1490 

1260 

1240 

1020 

IOIO 

1540 

1500 

1310 

1240 

1080 

1  100 

1550 

1450 

I320 

1290 

1090 

1090 

1490 

1520 

1  2DO 

1300 

IO4O 

1090 

1460 

1480 

1256 

1270 

IO4O 

1040 

1460 

143° 

1240 

1220 

IOIO 

IOIO 

1490 

143° 

1270 

1242 

1040 

IO2O 

1530 

1500 

1330 

1340 

1072 

1094 

!54Q 
1460 

1520 
1500 

'350 
1260 

I32O 
1280 

1080 

1050 

1080 

1030 

!53Q 

1560 

1330 

1340 

1072 

1094 

1500 

1480 

1270 

I3OO 

1030 

1040 

1460 

1490 

J43° 
1460 

1240 
1260 

I2IO 
1280 

IOIO 

1030 

IOIO 

1082 

1480 

1500 

1250 

I24O 

1020 

IO2O 

1498 

1480 

1272 

1292 

1046 

1063 

Mean  1495  Sm- 

1483  gm. 

I28ogm 

.  1276  gm. 

1044  gm.  1061  gm. 

Ratio       i 

.008 

1.003 

0.984 

The  mean  ratio  of  "  with  iron  "  to  "  with  lead,"  as  found  from 
these  numbers,  is  0.9997.  Of  course,  there  is  something  of  luck 
in  the  very  close  approach  of  this  final  ratio  to  i. 

Similar  luck  is  not  evident  in  the  figures  given  in  the  next 
table,  which  shows  the  results  obtained  by  ten  different  groups 
of  students,  usually  four  in  a  group,  from  exercises 
Illustration:  37  an^  3$  of  the  Harvard  Descriptive  List  of  Ele- 
mentary  Exercises  in  Physics.  These  experiments 
deal  with  action  and  reaction,  and  undertake  to 
compare,  in  terms  of  an  arbitrary  unit,  the  total  momentum  of  two 
balls  before  collision  with  their  total  momentum  after  collision. 

In  case  i,  the  smaller  ball  strikes  the  larger  at  rest;  in  case 
2,  the  larger  ball  strikes  the  smaller  at  rest;  in  case  3,  the  two 
balls  meet,  each  being  in  motion  ;  in  case  4,  the  smaller  ball, 
encircled  by  a  belt  of  putty  to  make  the  collision  inelastic,  is 
struck,  at  rest,  by  the  larger  ball. 

The  momentum  of  each  ball  before  collision  is  estimated 
from  its  mass  and  the  horizontal  distance  it  has  swung,  as  a 


DISCOVERY,    VERIFICATION,    OR  INQUIRY     285 

pendulum,  to  the  collision,  which  occurs  when  each  ball  is  in 
its  position  of  rest.  The  momentum  of  each  ball  after  collision 
is  estimated  from  its  mass  and  the  distance  it  swings  after 
collision.  As  friction  of  the  air  does  produce  a  perceptible 
effect,  even  in  a  single  swing,  this  method  of  estimation  gives 
a  slightly  too  great  numerical  value  for  the  momentum  of  each 
ball  before  collision,  and  a  slightly  too  small  value  for  the 
momentum  of  each  after  collision.  This  defect  plainly  shows 
in  the  results  here  put  down,  which  were  reported  by  a  class 
under  my  instruction  in  1900-1901. 


ist  Case. 

zd  Case. 

3d  Case. 

4th  Case. 

Momentum. 

Momentum. 

Momentum. 

Momentum. 

Before. 

After. 

Before. 

After. 

Before. 

After. 

Before. 

After. 

1485 

H97 

2799 

3005 

2058 

22O7 

5598 

5378 

1554 

1558 

2725 

2853 

1948 

1762 

5450 

5069 

1516 

1282 

2447 

2727 

1989 

2015 

5495 

5455 

T5°3 

1518 

1826 

1440 

1074 

1180 

3652 

3837 

1569 

1598 

2689 

2637 

1904 

2054 

5378 

5534 

1458 

2745 

2626 

1988 

1729 

5490 

5°94 

1500 

1683 

1800 

1895 

1061 

1129 

3621 

3627 

1449 

1448 

2717 

2512 

1993 

1992 

5435 

5238 

1554 

1558 

2725 

2852 

1948 

1762 

5449 

5069 

1475 

1250 

1921 

1883 

I  201 

III2 

3817 

3706 

Mean  1512 

1485 

2439 

2343 

I7l6 

1694 

4939 

4803 

Ratio  '  i 

.Oil 

1.041 

I.C 

'13 

i 

.028 

The  mean  ratio  is  1.023.  The  air  friction,  already  mentioned, 
would  go  far  toward  explaining  the  departure  of  this  ratio  from 
unity. 

A  very  troublesome  exercise,  from  the  point  of  view  of  accu- 
racy of  results,  is  that  in  which  an  attempt  is  made  to  find  the 
density  of  air  at  atmospheric  pressure  by  noting  the   Density  of 
loss  of  weight  of  a  large  bottle  of  known  capacity  Air 
from  which  a  measured  fraction  of  the  air  is  pumped  Experi 
out,  the  weighing  being  done  on  the  familiar  platform  balance 
mentioned  in  Chapter  IV.      Some  teachers  maintain  that  it  is 
not  worth  while  to  try  to  do  this  experiment,  unless  a  more 
accurate    balance  than    this  one    is  used ;  and  I  must  admit 
that  my  students,  usually  working  in  pairs  in  this  exercise,  get 
some  very  wild  results  from  their  observations. 


286      DISCOVERY,    VERIFICATION,    OR  INQUIRY 

The  time  allowed  for  the  actual  performance  of  the  exercise 
is  about  an  hour  and  a  half,  and  in  this  time  each  pair  of 
students  is  expected  to  go  through  the  experiment  three 
times.  Very  careful  instructions  are  given  as  to  the  use  of  the 
balance. 

The  following  results  are  obtained  from  data  reported  by 
members  of  a  class  working  under  my  supervision  in  the  fall  of 
1901.  I  have  taken  twenty  consecutive  reports  from  the  record- 
book,  passing  over  only  such  as  were  incomplete  or  were  dupli- 
cates of  others  taken.  The  calculations  of  results  I  have  made 
myself,  as  my  main  object  at  this  moment  is  to  show  how  good 
or  how  bad  data  students  get  with  the  apparatus  at  their  com- 
mand in  this  exercise.  The  capacity  of  the  bottle  used  was 
about  190001.  cm.  in  all  cases.  The  barometric  pressure  was 
about  76.7.  In  most  cases  the  pumps  took  out  about  90  per 
cent  of  the  air.  It  appears  that  in  most  cases  the  pressure- 
gauge  was  read  with  tolerable  accuracy,  though  there  is  one 
case  of  apparently  large  error  in  this  operation,  so  that  most 
of  the  inaccuracy  of  the  results  is  to  be  charged  to  incorrect 
weighing.  The  results  are  as  follows  : 

Density  of  air  in  the  neighbourhood  of  20°  C.  under  a  pres- 
sure of  about  76.7  cm.  of  mercury: 


.00125 

[.00047] 

.00129 

.00119 

.00123 

.00117 

[.00059] 

[.00456]  • 

.00115 

.00102 

.OOI2O 

.00083 

.00140 

[.00174] 

.00084 

.00104 

.00130 

.00115 

.00110 

.00133 

I  have  bracketed  four  of  these  quantities,  because  I  think  the 
badness  of  these  four  is  not'  properly  chargeable  to  the  poor 
performance  of  the  balance.  The  [.00174]  is  obtained  from 
data  which  appear  to  be  affected  by  a  very  large  pressure-gauge 
error.  The  values  [.00047]  an(^  [•00059]  are  fr°m  data  in 
which  an  error  of  i  gm.  or  more  is  apparently  made  in  the 
weighing,  and  the  value  [.00456]  involves  an  error  of  about 


DISCOVERY,    VERIFICATION,    OR  INQUIRY     287 

5  gms.  Errors  of  such  magnitudes  cannot  fairly  be  laid  to  the 
balance.  They  are  blunders,  such  as  might  be  made  with  a 
much  better  balance.  The  variation  among  the  remaining 
values  is  large,  but  not,  in  my  opinion,  so  large  as  to  destroy 
the  value  of  the  exercise,  which  is  an  instructive  one.  The 
bracketed  results  being  omitted,  the  mean  of  the  values  here 
given  is  .00116-,  which  is  about  5%  low. 

I  have  intimated  that  the  numbers  given  in  the  preceding 
tables  are  culled,  to  some  extent,  from  the  reports  handed  in  by 
students,  many  reports  being  so  defective  as  to  show  pupiis» 
that  the  makers  have  failed  to  understand  the  ex-  Blunders. 
periment  or  have  blundered  seriously  in  their  calculations. 
The  practice,  which  I  commonly  follow,  of  leaving  the  class 
quite  uninstructed  as  to  the  magnitude  of  the  numerical  result 
to  be  expected  in  any  case,  has  this  disadvantage,  if  disadvan- 
tage it  be,  that  the  student  frequently  does  not  know,  before  he 
hands  in  his  result,  whether  it  is  right  or  absurdly  wrong.  This 
leaves  the  boy  free  to  make  all  the  mathematical  errors  of  which 
he  is  capable  ;  and  the  number  and  variety  of  these  which  he 
can  put  into  a  simple  calculation,  especially  if  it  involves  a 
trifle  of  algebra,  is  the  despair  of  the  teacher,  —  I  cannot  say 
the  wonder  of  the  teacher,  for  the  phenomenon,  remarkable  as 
it  is,  soon  fails  to  excite  surprise. 

I  have  sometimes  supposed  myself  to  be  afflicted  in  a  peculiar 
degree  by  this  kind  of  shortcoming  on  the  part  of  my  students, 
who,  in  that  one  of  my  classes  which  has  to  do  with  such  work 
as  we  have  been  discussing,  are  for  the  most  part  youths  who 
have  entered  college  with  a  "  condition "  in  physics ;  that  is, 
they  are  a  picked  class,  selected  by  this  criterion,  that  they 
have  been  unable  or  unwilling  to  learn  physics  in  school.  But 
I  find  upon  inquiry  that  other  teachers,  not  only  in  this  country 
but  in  England  also,  report  a  similar  weakness  in  their  pupils. 
Mathematical  feebleness  and  fallibility  are  the  birthright  of  no 
small  part  of  every  class  beginning  physics.  The  only  question 
is,  what  to  do  about  it. 

My  own  practice,  which  I  do  not  recommend  for  schools,  is 


288     DISCOVERY,   VERIFICATION,  OR  INQUIRY 

to  put  my  students  on  their  own  responsibility,  and  require 
them  to  stand  or  fall  by  the  first  report  they  make  on  an  exer- 
Repetition  of  c^se<  ^  a  student  wishes  to  repeat  an  exercise,  or 
Exercises.  repeat  a  calculation,  after  finding  that  his  first  re- 
port is  unsatisfactory,  he  is  usually  permitted  to  do  so,  but 
with  the  understanding  that  a  good  second  report  is  not  to 
be  taken  at  the  same  value  as  a  good  first  report ;  and  repeti- 
tions under  these  conditions  are  rather  infrequent.  Thus  the 
full  measure  of  his  shortcomings  is  often  not  realized  by  a 
heedless  student  until  the  half  yearly  day  of  reckoning  comes, 
and  then  he  is  likely  to  be  woefully  surprised  at  the  fix  in 
which  he  finds  himself.  If  I  were  teaching  in  a  school  with 
pupils  some  years  younger,  I  should  no  doubt  make  a  prac- 
tice of  requiring  them  to  repeat,  and  improve  on,  work  badly 
done. 


CHAPTER  VII 

THE   TECHNIQUE   OF  LABORATORY  MANAGEMENT 
REFERENCES. 

Eastern  Association  of  Physics  Teachers.  Report  on  Methods  of  In- 
struction in  Physics  in  Secondary  Schools.  1900. 

Strong,  E.  A.  Physics  in  The  High  Schools  of  Michigan.  SCHOOL 
REVIEW.  April,  1899.  Pp.  242-245. 

Threlfall,  R.  On  Laboratory  Arts.  London  and  New  York,  Mac- 
millan.  1898.  Pp.  338. 

IN  the  preceding  chapter  we  have  discussed  the  spirit  and 
object  of  laboratory  work.  We  have  now  to  consider  what  may 
be  called  the  technique  of  laboratory  management. 

One  of  the  most  important  questions  to  be  considered  under 
the  heading  of  this  chapter  is  whether  a  class  should  be  taken 
through  its  laboratory  work  with  an  even  front,  all  Report  on 
the  members  of  any  laboratory  section  doing  the  Methods, 
same  experiment  at  the  same  time,  or  whether  a  more  open  and 
irregular  formation  of  the  forces  engaged  should  prevail.     On 
this  question  the  Report  on  Methods  of  Instruction,  by  a  Com- 
mittee of  the  Eastern  Association  l  of  Physics  Teachers,  issued 
in  1900,  has  something  to  say. 

1  The  geographical  range  of  inquiry  on  which  this  report  is  based 
was  much  wider  than  the  title  of  the  association  would  indicate,  as  the 
following  quotation  from  the  report  will  show: 

"  Responses  to  this  circular  were  received  from  one  hundred  and 
seventy-nine  (179)  teachers  of  physics,  representing  geographically  twenty- 
five  (25)  States  and  territories,  besides  the  District  of  Columbia." 

Although  I  shall  have  occasion  to  criticise  the  report  in  one  or  two 
particulars,  I  regard  it  as  a  valuable  document,  most  of  its  recommenda- 
tions being,  in  my  opinion,  excellent.  The  very  fact  of  such  an  inquiry 
and  discussion  as  this  report  represents  is  a  most  encouraging  indication 
of  the  zeal  and  intelligence  now  common  among  teachers  of  physics.  A 
somewhat  similar  enterprise  was  conducted  some  years  ago  by  an  asso- 
ciation of  Colorado  teachers. 


290  LAB  OR  A  TOR  Y  MANA  CEMENT 

Among  the  propositions  set  forth  by  the  committee  in  its 
introductory  circular,  sent  out  for  comment  and  discussion,  was 
the  following  :  "  (e)  With  large  divisions,  it  is  economy  of  time 
and  energy  for  all  the  pupils  to  be  at  work  simultaneously  upon 
the  same  problem  [laboratory  exercise]  whenever  the  character 
of  the  work  will  permit.'7 

After  the  replies  had  been  received,  the  committee  reported 
as  follows  :  "  Simultaneous  work  upon  the  same  problem  by  all 

pupils  in  the  laboratory  is  not  to  be  recommended 
Even  Front?     r  r      _         __7. 

as  a  rule.     When,  however,  the  laboratory  divisions 

are  much  too  large  for  the  teaching  force  engaged,  this  seems 
to  be  the  only  practicable  plan,  although  its  educational  value 
is  questionable,  and  the  great  expense  caused  by  the  necessary 
duplication  of  apparatus  would  prevent  its  adoption  in  many 
schools,  and  preclude  its  application  to  problems  with  which 
costly  apparatus  must  be  employed.'7 

The  reasons  for  this  change  of  position  on  the  part  of  the 
committee,  so  far  as  they  are  expressly  set  forth  in  the  report, 
are  contained  in  the  following  passage:  "The  proposition" 
(e)  "  was  assented  to  with  much  hesitancy  by  many,  although 
there  were  some  who  seemed  to  think  that  such  an  arrange- 
ment would  work  well ;  in  fact,  those  who  have  large 
divisions  generally  state  that  this  is  their  usual  manner  of  work- 
ing. We  note  a  few  of  the  remarks  upon  this  question :  '  I 
think  better  results  may  be  obtained  with  the  whole  class  working 
on  the  same  problem.'  'The  character  of  the  work  and  the 
difference  existing  among  pupils  will  never  permit  its  efficient 
application.'  'Lack  of  apparatus  would  forbid  in  most  high 
schools.'  '  This  method  is  a  very  poor  method  and  should  be 
adopted  only  as  a  last  resort.'  '  Works  toward  mechanical  results 
in  California?  '  Too  much  like  "  nickeHn-the-slot "  work  ! ' " 

This  statement  of  reasons  seems  to  me  far  from  conclusive, 
and  I  cannot  help  thinking  that  the  committee  was  hasty  in  ad- 
mitting, as  it  seems  to  do,  that  the  simultaneous  method  is  only 
a  last  resort  for  teachers  overborne  by  too  large  sections. 

Why  is  the  "educational  value"  of  the  method  "question- 


LABORATORY  MANAGEMENT  291 

able "  ?  The  essence  of  the  method  is,  the  same  sequence  of 
exercises  for  all  pupils  and  opportunity  for  convenient,  econom- 
ical and  timely  discussion  of  these  exercises  by  Wastefulness 
the  teacher  and  the  class.  Do  considerations  of  of  Irregular 
"educational  value"  require  a  sequence  espe- 
cially adapted  to  each  pupil?  Do  they  require  that  the 
explanations  and  discussions  which  should  accompany  every 
exercise  shall  be  repeated  between  the  teacher  and  each  single 
pupil  of  a  squad  of  fifteen,  the  limit  recommended  by  the  com- 
mittee for  the  size  of  a  laboratory  division?  What  is  more 
wasteful  of  the  teacher's  time,  more  cruelly  exhausting  of  his 
nervous  energy,  than  the  constant  and  needless  repetition  of 
oral  instructions  and  explanations? 

The  only  way,  so  far  as  I  can  see,  to  avoid  such  a  painful 
labour  where  the  irregular  order  of  progress  prevails,  is  so  to 
arrange  the  apparatus  that  the  printed  or  written  directions  will 
be  sufficient  to  guide  the  pupil  in  its  use,  without  oral  instruc- 
tion. But  this  will  have  a  tendency  to  work  the  exercises  into 
such  forms  that  the  pupil  cannot  go  astray  therein,  the  true 
"  nickel-in-the-slot "  method. 

"  Lack  of  apparatus  would  forbid  [the  use  of  the  simultaneous 
method]  in  most  high  schools,"  is  one  comment.  But  is  this 
true?  In  small  high  schools  the  reduplication  of  Reduplication 
apparatus  required  by  this  method  is  moderate,  and  of  Apparatus, 
as  for  the  large  high  schools,  according  to  the  committee, 
"  those  who  have  large  divisions  generally  state  that  this  is  thejr 
usual  manner  of  working."  That  is,  the  thing  declared  imprac- 
ticable is  done  and  done  habitually.  The  outlay  of  money 
needed  to  provide  a  squad  of  fifteen  with  the  apparatus  for 
elementary  laboratory  work  in  the  simultaneous  method  is  not 
formidable.  Any  school  board  which  hesitates  to  make  it,  and 
yet  throws  the  burden  of  laboratory  instruction  upon  the  teacher, 
should  read  again  the  "Song  of  the  Shirt." 

It  is  true  that  a  rigid  following  of  the  method  in  question 
would 'prevent  any  one  pupil  from  doing  more  laboratory  work 
than  any  other.  This  might  or  might  not  be  unfortunate  ;  but 


292  LABORATORY  MANAGEMENT 

it  is  not  necessary  to  be  absolutely  strict  in  the  practice  of 
this  method.  It  is  comparatively  easy  to  devise  supplementary 
Elasticity  of  exercises  for  the  more  rapid  workers,  to  be  intro- 
Method.  duced  as  occasion  requires.  For  example,  if  one 

boy  measures  the  expansion  of  brass  only,  another  may  measure 
also  the  expansion  of  iron. 

Moreover,  it  is  very  good  practice  for  even  the  best  pupil  to 
repeat  an  experiment,  going  over  it  as  many  times  as  the 
length  of  the  laboratory  period  will  permit,  watching  for  varia- 
tions and  studying  for  improvements  in  his  own  work.  Finally, 
there  are  always  numerical  problems  which  may  well  occupy 
the  attention  of  the  exceptionally  rapid  worker. 

It  must  be  remembered  that  the  method  of  irregular  progress 
does  not  necessarily  imply  that  one  pupil  will,  in  the  end,  have 
had  more  opportunity  and  done  more  work  than  his  less  effi- 
cient classmate.  Adaptation  of  work  to  individual  capacity  is 
a  problem  in  itself.  It  can  be  worked  out  best,  other  tilings 
being  equal,  by  the  teacher  who  has  made  the  best  disposition 
of  his  other  work,  and  has  thereby  conserved  his  own  energy 
and  that  of  his  pupils. 

We  may  next  consider  what  is  the  proper  size  of  a  laboratory 

division.     The   Committee   Report   from  which    I   have  been 

quoting  in  this  chapter  declares  that  "  the  number 

51Z6  01 

Laboratory  of  pupils  in  a  laboratory  division  should  be  about 
ten  or  twelve,  and  should  not  exceed  fifteen  for  one 
teacher."  This  recommendation  accords  well  with  the  opinion 
which  I  have  long  held  and  frequently  expressed.  In  a  large 
college  class,  made  up  to  a  very  considerable  extent  of  young 
men  who  have  been  over  the  same  course  of  work  once  before,  I 
have  sections  of  twenty-five  or  thirty,  in  charge  of  a  single  assist- 
ant, but  I  am  not  entirely  satisfied  with  this  arrangement. 

A  certain  amount  of  direct  personal  oversight  and  criticism, 
while  the  exercise  is  in  progress,  is  needed  by  most  young 
pupils.  As  a  rule,  the  teacher  should  be  able  to  look  at  the 
work  of  every  member  of  the  division  during  every  laboratory 
period. 


LABORATORY  MANAGEMENT  293 

Should  the  pupils  work  singly,  though  simulta-  individual  or 
neously,  or  in  groups,  each  group  having  one  set  Group  Work? 
of  apparatus? 

There  are  some  familiar  and  important  experiments  which 
cannot  well  be  done  by  a  single  pupil;  there  are  undeniable 
advantages  in  serious  and  honest  consultation  between  members 
of  the  class,  in  the  presence  of  the  apparatus.  But,  on  the 
whole,  I  believe  that  co-operation  works  badly.  There  is  divi- 
sion of  responsibility.  One  or  two  members  of  a  group  will 
dominate  it.  If  they  happen  to  be  interested  and  energetic, 
they  will  do  more  than  their  fair  share  of  the  work,  leaving  the 
others  as  spectators ;  if  they  are  indifferent  and  lazy,  they  will 
impose  on  the  others  careless  and  inaccurate  methods.  Group 
work  is,  according  to  my  experience,  and  I  am  compelled  to 
use  it  to  some  extent  in  one  of  my  classes,  worrying  to  the 
instructor  and  rather  unsatisfactory  to  the  students. 

I  must  admit,  however,  that  working  in  groups  of  two  is  the 
common  practice  in  one  of  the  most  successful  and  satisfactory 
school  laboratories  with  which  I  am  acquainted.  A  great  deal 
depends  on  the  spirit  which  the  teacher  is  able  to  inspire  in 
his  class. 

The  period  for  a  laboratory  exercise  should,  by  general  agree- 
ment, be  twice  the  length  of  the  ordinary  school  period,  as  a 
rule.     There  are,  however,  many  experiments  such 
as  beginners  naturally  take,  those  having  to  do  with  Laboratory 
specific  gravity,  for  example,   which  can  well  be  Exercise- 
done  in  a  single  school  period,  if  the  work  is  well  planned.     It 
is  my  opinion  that,  if  the  whole  laboratory  course  is  extended 
through  two  years,  as  it  is  in  many  schools,  the  work  of  the  first 
year  may  well  be  done  in  single  school  periods,  the  more  diffi- 
cult and  longer  experiments  being  taken  in  the  second  year. 

It  was  with  this  possibility  in  view  that  the  set  of  experiments 
given  in  the  Harvard  Descriptive  List  was  divided  into  a  First 
Part  and  a  Second  Part.  It  would  be  a  pity  to  let  the  real  or 
supposed  impossibility  of  arranging  for  double  periods  prevent 
the  beginning  of  laboratory  work.  But  for  such  experiments, 


294  LABORATORY  MANAGEMENT 

or  exercises,  as  most  of  those  given  in  the  Second  Part  of  the 
list  just  mentioned  double  periods  are  needed. 

According  to  the  report  which  has  been  referred  to  so  often 
in  this  chapter,  "  Both  teacher  and  pupil  should  be  prepared 
The  Teacher's  beforehand  for  the  work  to  be  done  in  the  labo- 
Preparation.  ratory.  The  kind  and  extent  of  this  preparation 
should  depend  upon  the  character  of  the  exercise,  the  manner 
in  which  it  is  to  be  approached,  its  relation  to  other  work, 
etc."  This  merely  needs  amplification  and  illustration.  The 
preparation  demanded  of  the  teacher  is  physical  as  well  as  mental. 
He  must  know  the  theory  of  the  experiment  and  must  have 
such  knowledge  of  its  actual  operation  as  can  be  acquired  in 
no  other  way  than  by  going  through  it  with  such  apparatus  as 
the  pupil  is  to  use.  Unless  he  has  done  the  experiment  many 
times  in  this  way,  he  should  have  done  it  recently.  He  should 
make  sure  that  all  the  apparatus  which  will  be  needed  by  the 
class  is  in  good  condition  and  in  the  right  place,  not  only  the 
large  things,  but  also  the  little  things,  not  only  bottles  and  spring 
balances,  but  also  thread  for  suspending  the  bottles  on  the 
balances.  Not  only  Bunsen  burners,  and  boilers,  etc.,  but  large 
stoppers  for  the  tops  of  the  boilers  and  perhaps  small  stoppers 
to  close  holes  in  the  large  stoppers. 

Unless  these  small  necessaries  are  thought  of  in  advance  and 
provided,  the  work  of  the  class  is  presently  suspended,  while 
the  instructor  trots  excitedly  about  the  laboratory,  ransacking 
closets  and  drawers  in  a  possibly  vain  attempt  to  supply  the 
needed  article.  This  wastes  time  and  demoralizes  the  class. 

Almost  equally  bad  is  the  habit  of  shouting  tardy  explanations 
and  instructions  to  the  section  after  it  has  begun  work.  If  the 
teacher  cannot  practice  foresight,  he  must  not  expect  his  pupils 
to  exercise  care. 

When  a  printed  manual,  giving  detailed  directions  for  labo- 
ratory work,  is  used,  it  is  hardly  necessary  or  advisable  for  the 
Use  of  a  teacher  to  go  completely  through  the  experiments 

Manual.  j^y  way  of  example  in  the  presence  of  the  class, 

nor  should  he  get  into  the  habit  of  repeating  to  the  class  the 


LABORATORY  MANAGEMENT  295 

directions  of  the  manual  ;  for  such  a  practice  lessens  the  pupil's 
feeling  of  obligation  to  read  the  directions  carefully  and  robs 
him  of  the  discipline  which  he  should  get  by  interpreting  these 
directions  for  himself.  The  habit  of  waiting  or  asking  to  be  told 
things  that  are  in  plain  print  before  him,  is  one  of  the  besetting 
vices  of  the  American  youth  when  he  comes  to  college. 

I  have  discussed  elsewhere  (Chapter  IV.),  at  considerable 
length,  the  question  whether  the  pupil   should   be  told  in  ad- 

vance iust  what  he  is  expected  to  find  in  his  ex- 

The  Prepa- 
periments,  the  exact  law,  if  he  is  looking  for  a  law,   ration  of  the 


the  exact  value  of  the  numerical  constant,  if  he  is 
looking  for  such  a  constant.  In  my  opinion  he  should  not, 
as  a  rule,  be  so  informed.  But  he  should  know  enough  about 
the  proposed  pvpprrmprii-  tg^enabjE.  .Jugi!  to  get  about  it 
promptly,  when  the  arjrmratus  is  placed  at  his  disposal,  and  to 
go  through  it  with  a  good  notion"  of  what  he  is  driving  at. 
Accordingly,  it  is  well  for  the  teacher  to  exhibit  the  apparatus 
to  the  class  iir^v!ncT*oft:he  laboratory  work,  with  veriTbrief 
remarks  concerning  its  use,  it  it  amTTtTe^printed  directions  are 
satisfactory,  with  more  extended  comments  and  directions,  if 
the  apparatus  or  the  manual  is  defective.  After  such  an  expo- 
sition the  pupil  can  read  the  directions  more  intelligently  than 
if  he  had  not  seen  the  apparatus,  and  he  should  be  expected 
to  read  them  through  before  beginning  the  laboratory  work. 

During  the  actual   progress  of  the  exercise  the 
teacher  should  maintain  a  vigilant  oversight  and  be   {JjJ^f1* 
unsparing  of  helpful  criticism,  but  he   should  not   Meddling. 
meddle  and  he  should  not  demand  impossibilities. 

Boys  working  singly,  with  well-devised  apparatus  and  well- 
considered  methods,  will  almost  always  show  an  excellent  spirit 
in  their  laboratory  manipulations  and  not  infrequently  a  com- 
mendable degree  of  ingenuity.  Their  zeal,  however,  does  not 
always  inspire  them  to  put  away  their  apparatus  when  they  have 
done  with  it.  For  example,  failure  to  replace  their  weights  in 
proper  holders  after  use  of  a  balance  is  one  of  the  minor  evils 
with  which  a  teacher  has  to  deal.  The  pupil  should  find  his 


296  LABORATORY  MANAGEMENT 

apparatus   in   good  condition   and    should   leave   it   in   good 
condition. 

As  to  the  proper  character  of  the  pupil's  record  of  his  work, 
Form  of  *  can  narcUy  give  better  advice  than  by  making  one 

Record.  more  quotation  from  the  report  now  so  familiar  to 

readers  of  this  chapter :  "  The  pupil  should  keep  a  laboratory 
note-book  which  should  contain  a  concise  statement  of : 

(a)  Problem  to  be  solved. 

(b)  Method  of  work. 

(c)  Apparatus   and   material  used ;    and,  in    many  cases,  a 
rough  sketch  of  the  arrangement  of  the  apparatus. 

(d)  Necessary  formulas  and  computations. 

(e)  Observed  results,  together  with  such  inferences  as  the 
pupil  may  reasonably  be  expected  to  make." 

Nothing  is  here  expressly  said  concerning  the  observations, 
which  are,  presumably,  to  be  recorded  in  connection  with  the 
"  Method  of  work."  It  will  probably  be  necessary  for  the 
teacher  at  the  beginning  of  the  course  to  prescribe  pretty  fully 
the  form  of  observation  record ;  but  the  pupils  should  become 
accustomed,  as  the  work  goes  on,  to  plan  their  own  arrange- 
ment of  the  facts  to  be  put  down.  The  effort  should  be  to  write 
what  is  essential,  and  only  what  is  essential,  and  all  in  such  a  form 
as  to  be  easily  intelligible  to  the  reader.  The  pupil  should  try 
to  make  such  a  record  as  would  be  most  useful  to  himself  years 
afterward,  if  he  should  have  the  task  of  taking  a  class  through 
the  same  experiments.  This  may  seem  to  be  asking  a  good 
deal  of  young  pupils,  and  of  course  they  will  fall  short  of  per- 
fection ;  but  the  thing  to  be  impressed  on  them  is  that  a  record 
should  tell  a  plain  tale  to  people  who  are  not  present  when  the 
record  is  made,  or  who,  through  lapse  of  time,  have  forgotten 
much  of  what  the  record  sets  forth. 

Of  course,  if  a  laboratory  manual  giving  detailed  directions 
for  the  work  is  used,  it  is  not  necessary  or  profitable  to  copy 
all  of  these  directions  into  a  note-book.  An  abstract  of  the 
method  should  be  given  in  the  pupil's  own  language  or  indi- 
cated by  the  recorded  observations. 


LABORATORY  MANAGEMENT 


297 


Practice  of  the  graphical  method  of  record,  by  means  of  the 
simplest  possible  drawings,  is  of  very  great  service  ;  for  it  re- 
quires the  pupil  really  to  study  his  apparatus,  and  yet,  by 
saving  many  words,  may  save  his  time  as  well  as  that  of  the 
reader. 

The  following  example  may  illustrate  some  of  the 
precepts  which  have  now  been  given : 


Illustration. 


Exercise Feb ,  , 

STUDY   OF   THE   ZERO-POINT   ERROR    AND    THE 
BOILING-POINT    ERROR   OF    A    CENTI- 
GRADE   THERMOMETER. 

The  general  method  used  was  the  one  given  in , 

but  the  boiler  used  was  different  from  the  one  shown   in  the  book, 


having  a  top  that  screwed  on  and 
ing  the  height  of  water  in  the  body 
of  the  boiler.  See  Fig.  13. 

The  thermometer  tested  was 

No It  had  a  paper  scale 

and  was  graduated  in  degrees,  the 
scale  extending  from  10°  below  o° 
to  110°  above. 

Reading  in  ice  and  water  (or 
snow)  before  heating  —  +0.2°. 

Reading  in   steam,  as   in    Fig. 

13.  =  99-7°- 

Reading  of  barometer  =  76.5  cm. 

Reading  of  thermometer  in 
steam  as  in  Fig.  13,  but  with  steam 
outlet  nearly  closed,  and  mercury 
gauge  as  in  Fig.  14,  =  101.1°. 

(Real  difference  of  level  of  the 
mercury  columns  about  4.2  cm. ; 
allowance  of  o.i  cm.  made  for  pres- 
sure of  water,  about  1.5  cm.,  in  left- 
hand  side  of  the  gauge.) 

Reading  in  steam,  with  steam 
escape  wide  open,  but  with  o° 
mark  just  above  top  of  stopper 

-93.70. 

Reading  in  ice  and  water  after 
heating  =  — 0.1°. 


a  water-gauge  at  the  side  for  show 


Fig.13. 


298  LABORATORY  MANAGEMENT 

Conclusions  :  The  thermometer  read  about  0.2°  too  high  in  ice  and 
water  at  first,  and  about  0.1°  too  low  at  the  last.     The  reason  for  this 
change  I  do  not  know,  but  it  appears  to  have  been  caused 
by  the  heating. 

The  thermometer,  with  bulb  and  stem  in  steam,  read 
99.7°  when  the  barometer  read  76.5  cm.,  0.5  cm.  above 

1        standard.     According  to  my  observations,  a  rise  of  pres- 
cnl  sure  equal  to  4.1  cm.  of  mercury  caused  a  rise  of  1.4  de- 
grees in  the  boiling  temperature.      This  is    (1.4-^-4.1) 
degrees  =  0.34  degree,  for  i  cm.     According  to  this,  if 
t*16  barometer  had  read  76  cm.,  instead  of  76.5,  the  ther- 
mometer would   have  read  about  (0.34  X  0.5)  degrees, 
=  0.17  degree,  lower  than  it  did  ;  that  is,  99.7°  —  o.  17°  =  99.5°,  nearly. 

Drawing  the  stem,  from  100°  to  o°,  out  of  the  steam,  while  the  bulb 
remained  in  the  steam,  lowered  the  reading  about  i°. 

The  next  recommendation  of  the  Eastern  Association  runs 
as  follows  :  "  The  laboratory  note-book  should  be  written  up  in 

Time  for  tne  ^a^oratory  at  tne  tmie  tne  wol"k  is  done.  The 
Record  and  writing  should  be  in  ink  so  that  the  original  entry 
Calculations.  cannot  ^Q  erased."  It  is  doubtful  whether,  under 
the  conditions  imposed  by  this  rule,  the  average  pupil  could 
be  expected  to  complete  such  a  record  and  discussion  as  that 
just  given,  unless  the  time  allowed  for  the  whole  exercise  were 
more  than  two  consecutive  school  periods.  Could  not  a  part 
of  the  work,  the  writing  out  of  conclusions,  be  done  later  and 
elsewhere?  If  not,  I  should  fear  that  the  observations  would 
be  hurried  and  unsatisfactory. 

It  is,  of  course,  desirable  to  discuss  the  observations  and  de- 
rive the  conclusions  as  promptly  as  may  be.  Promptness  saves 
time  and  contributes  toward  good  results.  But  independent 
thinking,  even  on  so  simple  a  problem  as  calculating  what  the 
thermometer  reading  would  be  if  the  barometer  reading  were 
changed  a  certain  amount,  the  calculation  to  be  on  the  basis 
of  the  pupil's  own  observation  of  the  effect  of  increased  pres- 
sure, keeps  the  ordinary  boy  thinking  for  a  considerable  time, 
unless  he  gets  very  effective  help  from  the  teacher  or  some  one 
else. 

It  is,  perhaps,  the  "some  one  else,"  the  possibly  injudicious 
guide  and  collaborator,  that  the  Eastern  Teachers  undertake  to 


LABORATORY  MANAGEMENT  299 

avoid  in  their  prescription  that  the  record  and  discussion  shall 
be  finished  at  once  and  in  the  laboratory.  I  must  admit  that 
there  is  danger  of  a  great  evil  from  this  side,  and  I  do  not  see 
how  to  avoid  it  altogether  without  following  the  strict  and  diffi- 
cult rule  which  they  lay  down.  This  danger,  however,  is  not 
peculiar  to  physics.  It  besets  all  work  not  done  under  the  eye 
of  the  teacher. 

It  is  true  that,  in  the  case  of  boys  applying  for  admission  to 
college,  the  college  may  require  the  teacher's  certificate  that 
the  note-book  is  the  candidate's  own  record  of  his  oversight  of 
own  laboratory  work,  but  it  is  evidently  unfair  to  Note-Book- 
ask  that  the  teacher  shall  have  seen  every  word  of  it  written,  or 
shall  have  made  sure  that  every  mental  operation  represented 
in  it  is  original  with  the  pupil.  That  the  actual  laboratory  work 
and  handwriting  are  the  pupil's  own,  the  teacher  can  reasonably 
be  expected  to  know  and  to  declare  ;  and  this  declaration 
assures  the  college  examiners  that  the  candidate  has  at  least 
gone  through  the  motions  of  using  apparatus  and  keeping 
a  record.  This  fact  raises  a  sufficient  presumption  in  his 
favour  to  justify  the  examiners  in  admitting  him  to  their 
tests.  The  mere  clerical  practice  of  keeping  an  orderly  note- 
book is  valuable  and  something  to  be  counted  in  the  candi- 
date's favour. 

If  teachers  find  it  readily  practicable  to  live  up  to  the  rule 
given  by  the  Eastern  Association,  well  and  good.  But  I  fear 
that  many  conscientious  teachers  have  expended  in  the  over- 
sight of  the  record  an  amount  of  care,  and  even  of  anxiety, 
quite  incommensurate  with  the  attention  given  to  it  by  the 
college  examiners,  and  quite  unnecessary  for  the  proper  func- 
tion of  the  note-book. 

The  practice  of  making  the  record  in  ink  from  the  start,  and 
in  such  form  that  it  will  not  have  to  be  rewritten,  is  an  excel- 
lent one.  A  copied,  or  rewritten,  record  is  sure  to  First  Record 
look  better  than  the  original,  but  it  is  not  the  main  Should  stand, 
object  or  virtue  of  a  record  to  look  well.  Note-books  should 
not  be  confounded  with  copy-books  for  the  practice  of  penman- 


300  LABORATORY  MANAGEMENT 

ship.  Moreover,  the  original  notes,  if  made  on  loose  sheets  as 
they  frequently  are  when  copying  is  intended,  are  very  likely  to 
be  misplaced  and  lost.  Taking  the  notes  in  one  book,  and  then 
copying  them  off  in  fair  form  into  another  book,  both  books 
being  preserved,  is  a  practice  which  avoids  this  difficulty ;  but  it 
involves  labour  which  is,  in  my  opinion,  unnecessary,  and,  on 
the  whole,  unprofitable. 

The  habit,  which  some  teachers  follow,  of  encouraging  their 
pupils  to  make  a  hasty  first  trial  of  an  experiment,  the  record  of 
Tentative  which  trial  is  not  preserved  unless  it  happens  to  be 
Work.  satisfactory,  seems  to  me  rather  objectionable,  as  it 

may  appear  to  warrant  the  practice  of  culling  observations  and 
leaving  out  those  which  do  not  accord  well  with  others. 

In  a  college  class,  made  up  largely  of  students  who  have 
failed  in  physics  at  the  admission  examination,  I  am  much  less 
"Data  regardful  of  the  note-book  than  I  should  be  in  a 

SUps."  school  with  younger  pupils.  My  practice  is  to  re- 

quire the  student  to  write  out  and  hand  in,  before  he  leaves  the 
laboratory,  a  brief  record  of  his  numerical  observations  in  the 
experiment  which  he  has  just  performed.  These  notes  he 
makes  on  a  slip  of  paper,  usually  about  3.5  X  4-5  inches, 
called  a  data  slip,  which  is  soon  pasted  into  a  large  scrap- 
book  under  the  student's  name,  four  pages  of  the  book  being 
devoted  to  his  record  for  the  whole  course.  A  similar  set  of 
notes,  with  such  amplifications  as  may  be  required,  usually 
very  few  or  none,  is  made  by  the  student  in  his  note-book. 

The  laboratory  exercise  for  each  student  in  this  course  comes 
once  a  week,  and  one  week  after  he  performs  any  experiment 

he  is  required  to  hand  in  the  worked-out  result  or 
"Result Slips."  .     .        .          .  .  .  ..     ... 

conclusion  from  this  experiment  on  a  result  slip, 

which  is  presently  pasted  by  one  edge  into  the  scrap-book,  just 
over  the  corresponding  data  slip,  to  which  it  is  like  in  form  and 
size.  The  result  must  be  such  as  the  data,  which  the  student 
has  had  no  opportunity  to  alter  while  working  out  his  result, 
will  yield. 

By  this  device,  I  have  at  any  time  during  the  year  a  bird's-eye 


LABORATORY  MANAGEMENT  301 

view  of  what  each  student  in  the  course  has  done  in  the  way  of 
laboratory  work. 

The  note-book  is  examined  only  twice  during  the  year,  and, 
as  it  is,  in  considerable  part,  a  duplicate  of  the  scrap-book  record, 
not  very  much  importance  is  attached  to  it.  I  feel,  however, 
that  it  would  be  an  injury  to  the  students  to  dispense  altogether 
with  the  note-book,  the  keeping  of  which  helps  to  keep  the 
lessons  of  the  course  in  their  minds.  It  will  be  seen  that  the 
practice  just  described  involves  some  copying,  but,  as  the 
records  are  usually  brief,  this  is  no  great  hardship. 

As  the  method  of  individual  laboratory  work  makes  each 
student's  data  differ  in  some  particulars  from  the  data  of  others, 
the  danger  of  illicit  practices  in  the  working  out  of  results  is  less 
than  one  might  at  first  suppose. 

It  is  my  frequent  practice  to  comment  briefly,  at  the   first 
convenient  opportunity,  on  the  character  of  the  results  yielded 
by  any  given  exercise,  illustrating  my  remarks,  which 
are  addressed  to  the  class  as  a  whole,  by  examples  Laboratory 
from   good   or   bad  reports,   and    exhibiting   such       or  ' 
tables   as   are    shown  in  the  preceding  chapter  of  this  book. 
True,  it  is  not  best  to  say  much  to  a  class  in  regard  to  the 
mental  or   moral   discipline   gained   from    any  study.     Young 
people  are  proverbially  averse  to  sermonizing,  and  like  to  feel 
an  immediate  motive  for  what  they  do.     Yet  one  of  the  most 
important  objects  of  laboratory  work,  properly  conducted,  is  to 
show  the  pupil  side  by  side  the  poor  results  of  poor  work,  physi- 
cal or  mental,  and  the  good  results  of  good  work.     There  is  a 
convincing  tangibility  about  the  results  of  definite  laboratory 
problems,  which  is  bound  to  make  an  impression. 

Moreover,  the  fact  that  a  large  number  of  moderately  good 
results  contribute  to  give  at  last  a  very  good  one,  positive  and 
negative  casual  errors  eliminating  each  other  in  the  long  run, 
though  certain  constant  errors  remain  to  be  investigated  and 
discussed,  —  this  is  a  truth  better  taught  in  the  concrete  than  in 
the  abstract,  and  certain  laboratory  exercises  are  peculiarly  well 
adapted  to  teach  the  lesson. 


302  LABOR  A  TOR  Y  MAN  A  GEMENT 

In  some  exercises,  which  relate  to  the  properties  of  individual 
objects,  the  specific  gravity  of  wooden  blocks,  for  example,  or 
Teacher's  ^ie  *°ca^  ^en§tn  °f  lenses,  the  different  members  of 
Record  of  a  class,  each  having  his  particular  object  to  work 
with,  may  correctly  get  different  results.  In  such 
cases,  the  teacher  should  mark  each  of  the  objects  studied  and 
make  such  a  record  of  its  properties  that  he  can  readily  tell 
whether  any  pupil,  studying  a  given  object,  has  or  has  not  done 
his  work  well.  Some  little  business  ability  is  needed  to  make 
and  keep  such  a  record  with  sufficient  accuracy  and  without  an 
unreasonable  amount  of  labour  and  worry.  But,  if  it  is  well 
planned  and  vigorously  kept  up,  it  will  amply  repay  what  it 
costs. 

The  obvious  fact  is  that  the  pupil  has  a  right  to  know,  and 
that  not  so  very  long  after  the  exercise  is  finished,  whether  he 
has  or  has  not  done  well  in  any  particular  task.  Without  such 
an  assurance  he  may  be  unduly  discouraged  or  unduly  confi- 
dent. This  being  the  case,  there  is  no  more  distressing  job  for 
the  teacher  than  that  of  trying,  without  an  adequate  knowledge 
of  the  facts,  to  pass  judgment  on  work  done. 

It  is  plain  enough  that  the  business  of  teaching  physics  by 
the  laboratory  method  imposes  on  some  one  a  large  amount  of 
Economy  of  Purety  mechanical  labour  in  the  preparation  and 
Teacher's  care  of  apparatus,  to  say  nothing  of  its  manufacture. 
It  is  the  duty  of  the  teacher,  who  needs,  of  course, 
to  be  continually  in  a  state  of  mental  activity  and  alertness,  to 
save  himself  all  unnecessary  physical  labour,  unless  he  happens 
to  be  so  constituted  as  to  enjoy  it. 

As  a  rule,  the  teacher  should  not  be  expected  to  make  appa- 
ratus which  he  can  find  ready  made  to  his  liking ;  for  he  is,  pre- 
Relief  from  sumably,  the  mental  superior  and  the  mechanical 
Manual  Labour,  inferior  of  the  workman  employed  by  the  manufac- 
turer. Even  in  the  handling  of  the  apparatus  after  it  is  in  the 
laboratory,  there  is  much  purely  physical  routine  labour  which  a 
person  who  can  hardly  read  and  write,  who  is  at  any  rate  less 
highly  trained  and  paid  than  the  teacher,  can  do  quite  well 


LA  BORA  TOR  Y  MA  NA  CEMENT  303 

enough.  Such  is  the  work  of  setting  out,  putting  away,  and 
cleaning  apparatus,  and  doing  errands  and  odd  jobs  of  various 
sorts.  The  most  satisfactory  person  for  this  kind  of  service  is 
one  who  is  entirely  satisfied  with  it,  takes  pride  in  it,  asks 
nothing  better  than  to  do  it,  for  reasonable  pay,  all  his  life.  I 
have  known  a  number  of  such  men,  all  Irish  as  it  has  happened, 
and  could  ask  for  no  better  service  than  they  have  habitually 
given,  after,  of  course,  some  painstaking  initial  training. 

But  I  am  aware  that  such  assistants  are  not  usually  to  be  had 
by  school-teachers  of  physics.  \  Such  teachers,  within  my  ac- 
quaintance, make  excellent  use  of  pupil  assistants,  or  of  'pren- 
tice teachers  who  are  willing  to  work  for  little  pay  for  a  year  or 
two  in  the  hope  of  acquiring  valuable  methods  and  experience. 
Sometimes  these  assistants  are  young  women. 

The  importance  of  having  some  orderly  and  natural  arrange- 
ment of  apparatus  for  the  moment  not  in  use,  instead  of  a  mere 
haphazard  distribution  which  only  one  person  can  Arrangement 
remember  and  which  no  one  can  explain,  is  too  of  Apparatus 
obvious  to  need  discussion.  There  is  much  in  favour  of  arranging 
apparatus,  as  nearly  as  may  be,  in  the  order  of  its  use  during  the 
year.  This  facilitates  not  only  the  parading  and  retirement  of 
apparatus  for  use,  but  also  its  survey  with  regard  to  future  needs. 
The  assistant  should  be  taught  to  look  weeks,  or  even  months, 
ahead  and  give  early  notice  of  any  lack,  in  order  that  the  worry 
and  expense  of  hasty  provision  at  the  last  may  be  avoided. 

Detailed  suggestions  for  the  arrangement  and  equipment  of  a 
laboratory  will  be  given  in  Chapter  XII. 


CHAPTER   VIII 

LECTURES   AND   RECITATIONS 

REFERENCES. 

Day,  R.  E.  Numerical  Examples  in  Heat.  London  and  New  York, 
Longmans,  Green  &  Co.  1889.  Pp.  176.  Gives  the  answers. 

Dolbear,  A.  E.  The  Art  of  Projection.  Boston,  Lee  &  Shepard. 
1892.  Pp.  178. 

Jones,  D.  E.  Examples  in  Physics.  London  and  New  York,  Mac- 
millan.  1900.  Pp.  348. 

Matthews,  C.  P.  and  Shearer,  J.  Problems  and  Questions  in  Physics. 
London  and  New  York,  Macmillan.  1897.  Pp.  247. 

Pierce,  E.  D.  Problems  in  Elementary  Physics.  New  York,  Henry 
Holt  &  Co.  1896.  Pp.  194. 

Snyder,  W.  H.  and  Palmer,  I.  O.  One  Thousand  Problems  in  Phy- 
sics. Boston,  Ginn  &  Co.  1900.  Pp.  142.  Gives  copies  of  Harvard 
admission  papers  in  physics. 

"Wright,  L.  Optical  Projection.  London  and  New  York,  Longmans, 
Green  &  Co.  1901.  Pp.  438. 

THERE  is  no  aspect  of  laboratory  work  more  striking  than 
the  poor  results  which  it,  when  standing  alone,  yields  in  written 
examinations  containing  problems  and  illustrations  not  explicitly 
occurring  in  the  laboratory. 

The  pupil  who  is  dull  or  lazy  at  mathematics  is  very  apt  to  feel 
that  the  mere  mechanical  performance  of  the  experiments  set 
Laborat  before  him  should,  by  any  reasonable  measure  and 

Work  not  appreciation  of  human  effort,  be  enough  to  save 
him.  He  "  has  been  there  every  time,"  has  even 
perhaps,  "  handed  in  all  of  the  results,"  right  or  wrong.  Is  it 
not,  then,  cruel  injustice  to  find  him  wanting  at  the  last, 
merely  because  he  "  could  n't  remember  all  those  formulas  and 
things,"  relating  to  specific  gravity,  fluid  pressure,  levers,  the 
parallelogram  of  forces,  etc.  The  fact  is,  that  most  boys  are 


LECTURES  AND  RECITATIONS  305 

more  inclined  to  work  hard  with  their  hands  than  with  their 
Heads,  more  willing  to  handle  apparatus  than  to  draw  any 
mental  results  from  their  activity.  Even  older  persons  have 
been  known  to  lack  the  resolution  and  the  intelligence  to 
read  all  the  lessons  their  own  experience  has  written.  Old 
or  young,  those  who  do  not  need  urging  and  guidance  are 
exceptional. 

The  laboratory  method  is  a  good  method,  so  far  as  it  goes. 
For  most  pupils  it  is  essential  to  a  firm  understanding,  a  clear 
vision,  a  just  perspective.  Experience  of  the  senses  is  the 
solid  ground  from  which  the  highest  flights  of  speculation  and 
theory  in  science  begin,  and  to  which  they  must  return,  with 
or  without  safety  to  the  voyager.  But  learning  by  experience 
is  a  plodding  method,  and  the  student  who  aspires  to  any  great 
height  or  breadth  of  intellectual  reach  must  not  confine  him- 
self to  it. 

There  are  several  more  or  less  distinct  functions  which  lec- 
tures and  recitations,  in  connection  with  laboratory  work,  can 
perform  ;  the  introductory  explanation  of  the  labo-   j^^^  of 
ratory  exercises,  the   derivation  and  discussion  of  Lectures  and 
immediate  results  from  these  exercises,  the  applica-  Recitations- 
tion  of  these  results  to  problems  not  given  for  solution  by  trial 
in  the  laboratory,  the  introduction  of  facts  and  principles  not 
touched  by  the    laboratory  work,  the    discussion    of  physical 
phenomena  in  general.     For  each  of  these   several  purposes 
the  methods  of  continuous  discourse  by  the  teacher,  of  inter- 
change of  question  and  answer  between  teacher  and  pupils, 
of   lecture-table   experimentation,    will    naturally   be   used    in 
turn. 

It  is  quite  impossible  to  assign  to  each  of  these  methods  its 
exact  relative  value,  or  to  state  the  proportions  in  which  it 
should  be  mixed  with  the  others.  The  teacher  perhaps  feels 
surest  that  he  is  interesting  his  class  when  he  is  showing 
experiments,  surest  that  he  is  getting  it  ready  for  an  examina- 
tion when  he  is  conducting  or  enduring  a  sort  of  cross-exam- 
ination, or  "quiz,"  surest  that  he  is  giving  a  comprehensive 


306  LECTURES  AND  RECITATIONS 

view  of  the  field  before  him,  or,  rather,  setting  forth  such  a 
view  for  those  to  take  who  can,  when  he  is  speaking  at  length 
and  without  interruption. 

Interest  is  almost  as  essential  to  the  boy  in  the  classroom  as 
to  the  horse  at  the  watering-trough,  and  therefore  experiments, 
or  at  least  some  form  of  stimulus  other  than  that  yielded  by 
the  pupil's  bare  sense  of  duty,  must  be  supplied,  when  the 
exercise  would  otherwise  be  one  of  unbroken  discourse  by  the 
teacher.  Which  of  us  does  not  feel  a  little  wearied  at  the 
end  of  an  hour's  talk  by  the  most  esteemed  philosopher? 
Young  pupils  must  not  be  expected  to  maintain  a  continuous 
mental  flight  for  more  than  a  few  minutes  at  a  time.  But  this 
warning  is  probably  unnecessary.  Few  teachers  in  schools 
have  time  to  construct  set  lectures  which  they  would  be  will- 
ing to  deliver  to  their  pupils. 

On  the  other  hand,  the  preparation  of  experiments  which 
can  be  depended  upon  to  come  off  at  the  right  time,  and  with 
the  right  effect,  is  a  serious  undertaking,  if  it  is  to  be  a  frequent 
one.  The  tendency  is,  therefore,  I  suspect,  for  the  teacher 
to  use  very  largely,  and  sometimes  to  abuse,  the  recitation 
or  "  quiz  "  method  of  keeping  his  class  occupied.  I  use  this 
last  phrase  advisedly ;  for  the  necessity,  imposed  by  the  school 
programme,  of  keeping  a  class  for  the  whole  of  a  certain  time 
in  a  recitation-room,  because  it  would  disturb  other  classes  to 
dismiss  this  one  before  the  stroke  of  the  bell,  must  often  lead 
to  expedients,  more  or  less  conscious,  for  killing  time. 

For  this  purpose  there  is  no  device  more  convenient  or  more 
serviceable  than  to  ask  questions,  especially  questions  which 
Abuse  of  the  tne  pupils  cannot  answer  with  readiness,  sometimes 
"Quiz."  questions  which  are  purposely  obscure,  and  so 

keep  up  a  kind  of  game  of  mystification  till  the  hour  is  over. 
As  an  example,  let  the  following  serve,  a  by  no  means  wholly 
imaginary  conversation  between  an  excellent  but  overworked 
teacher  of  science,  of  all  the  sciences,  and  his  class  in  physiology, 
the  subject  being  the  nervous  system,  and  the  especial  topic, 
the  sensations  of  a  person  who  has  lost  a  limb  : 


LECTURES  AND  RECITATIONS  307 

Teacher.  "  Now  I  have  heard  that  sometimes  a  man  whose 
leg  has  been  cut  off  will  complain  of  feeling  a  pain  in  the  toes 
of  the  foot  that  he  has  lost ;  he  will  perhaps  feel  as  if  his  toes 
were  cramped,  and  he  will  ask  some  one  to  go  and  get  the  leg 
and  —  do  what?  "  No  answer  from  the  class. 

Teacher.  "  Come  now,  children,  come,  speak  up  —  do  what  ? 
What  do  you  suppose  he  wants  them  to  do  with  the  leg?  " 

Pupil.    "  Bury  it." 

Teacher.   "  No,  it 's  buried  already,  we  will  suppose." 

Another  pupil.    "  Burn  it." 

Teacher.  "  Oh,  no  !  Come,  come,  children,  what  does  he 
want  them  to  do  with  the  leg?" 

Class  is  silent. 

Teacher,  as  the  bell  rings,  "  Straighten  out  the  toes" 

The  teacher  of  physics  is  fortunate  above  the  teachers  of 
most  other  subjects  in  having  always  the  legitimate  and  most 
salutary  resource  of  numerical  problems,  to  be  Numerical 
worked  out  on  the  spot,  and  to  be  discussed  proWems- 
immediately,  in  the  presence  of  all  the  class,  as  soon  as  they 
have  been  done,  rightly  or  wrongly,  by  a  considerable  number. 
Of  course  this  kind  of  exercise  can  be  overdone,  and  can  be 
mismanaged  otherwise.  It  is  usually  necessary  to  repress  one 
or  two  bright  pupils,  who  will  do  the  work  more  quickly  than 
others,  and  whose  superiority  in  this  particular,  if  not  judi- 
ciously ignored,  will  discourage  and  bring  to  a  standstill  the  rest 
of  the  class.  Moreover,  the  problems  to  be  given  should  be 
selected  with  care.  They  should  be  representative,  putting 
into  application  some  important  fact  or  principle,  theoretically 
rather  simple  and  numerically  brief.  Fortunately,  there  are 
good  printed  collections  of  problems  suitable  for  the  use  of 
beginners  in  physics,  books  for  which  we  cannot  too  gratefully 
thank  the  painstaking  and  public-spirited  makers. 

As  to  the  need  of  careful  preparation  for  lectures  and  for 
lecture-table  experiments,  there  is  little  call  for  ex-  preparation 
hortation.     Nearly  every  one  has  felt  or  has  seen   for  Lectures, 
the  melancholy  results  of  the  lack  of  such  preparation.     But 


308  LECTURES  AND  RECITATIONS 

something  of  possible  use  may  be  said  in  regard  to  the  way  in 
which  the  teacher  can  best  expend  his  effort. 

In  the  first  place  he  should  consider  whether  the  thing  which 
he  proposes  is  important,  and  in  the  next  place  whether  it  will 
produce  on  the  pupil  an  effect  which  will  justify  the  labour 
necessary  to  prepare  and  present  it. 

The  teacher  sometimes  undertakes  an  experiment  without 
fully  realizing  its  difficulties  or  the  imperfection  of  the  apparatus 
furnished  for  its  performance,  and,  having  ill  success  in  his  first 
trials,  becomes  roused  to  an  obstinate  effort  to  make  that  par- 
ticular thing  work.  Such  an  experience  may  do  no  especial 
harm,  may  even  be,  in  a  way,  profitable,  if  it  occurs  in  a  period 
of  leisure  when  there  is  time  to  make  experiments,  and  time  to 
make  mistakes ;  but  if  it  comes  shortly  before  the  lecture-hour, 
it  may  be  disastrous ;  for  men  of  a  certain  temperament,  when 
once  involved  in  struggle  with  difficulties,  can  think  of  nothing 
else  for  the  time  being,  and  if  they  do  come  tardily  to  the 
conclusion  to  leave  the  struggle  for  a  more  convenient  season, 
they  do  so  with  a  sense  of  defeat  that  unnerves  them  for  the 
prompt  and  confident  doing  of  things  that  are  commonly  quite 
within  their  powers.  Those  who  have  this  peculiar  form  of 
obstinacy,  which  may  be  a  source  of  strength  under  some 
conditions,  must  on  unimportant  occasions  beware  of  the  under- 
tow of  their  own  disposition  and  keep  well  above  it. 

In  the  way  of  lecture-table  experiments  it  is  not  necessarily 
the  laborious  achievement  that  counts.  The  little,  simple, 
What  Expert-  eas^Y  performed,  easily  seen,  but  striking,  exhibi- 
mentsare  tions  of  phenomena  and  illustrations  of  principle, 
happily  introduced  and  well  executed,  are  the  most 
profitable  things  to  show,  such,  for  example,  as  curious  hydro- 
static effects,  various  aspects  of  surface  tension,  experiments  with 
static  electricity,  etc. 

There  are,  of  course,  many  desirable  experiments  which  re- 
quire considerable  care  at  every  annual  repetition.  For  exam- 
ple, although  I  have  written  out  and  printed  careful  directions 
for  the  preparation  and  use  of  apparatus  for  the  sudden 


LECTURES  AND  RECITATIONS  309 

freezing  of  water,  I  could  not  now  undertake  to  make  this 
preparation  in  half  an  hour  with  confidence  of  success.  The 
method  is  to  boil  distilled  water  for  several  minutes  in  a  test- 
tube,  then  pour  oil  on  its  surface,  etc.  But  there  is  apparently 
a  difference  in  the  adaptability  of  test-tubes  for  this  use.  In 
some  of  them  the  condition  of  bumpy  boiling  does  not  occur, 
even  after  ebullition  has  been  maintained  for  several  minutes, 
and  I  never  feel  much  hope  that  sudden  freezing  will  occur 
where  "bumping"  has  not  occurred.  For  safety,  I  make 
ready  a  number  of  tubes,  three  or  four,  set  them  all  to 
cool  in  ice-water,  and  finally,  in  the  presence  of  the  class,  try 
one  after  another  in  the  freezing  mixture  till  one  has  proved  a 
success  or  till  all  have  proved  failures.  Similarly,  in  making 
preparation  for  the  freezing  of  water  during  its  own  boiling, 
over  sulphuric  acid  and  under  the  bell-jar  of  an  air-pump, 
much  care  is  necessary.  The  pump  must  be  in  such  con- 
dition that  it  will  lower  the  mercury  gauge  nearly  to  0.45  cm., 
and  a  pump  which  is  subject  to  much  and  varied  uses  is  not 
always  in  this  state  of  effectiveness. 

Whenever  a  teacher  finds  that  an  experiment  works  well, 
subjectively  and  objectively,  in  itself  and  on  the  class,  he  should 
leave  the  apparatus  for  this  experiment  in  the  most  LookFor- 
secure  and  convenient  condition  for  use  the  next  ward  a  Year, 
year,  and  should  make,  if  possible,  such  brief  notes  in  regard  to 
its  use  as  will  make  all  further  tentative  experimentation  with  it 
unnecessary. 

As  a  rule,  all  experiments,  whether  simple  or  otherwise, 
should  be  tried  anew  before  each  exhibition  of  them  ;  there  are 

so  many  ways  in  which  they  can  go  wrong.     Annual 

...  ...  Practice. 

practice  m  the  art  of  picking  up  bits  of  paper  by 

means  of  an  electrified  rod  of  gutta-percha  might  seem  unnec- 
essary care;  but  I  consider  it  worth  while.  Sometimes  the 
paper  does  not  come  up. 

Even  when  an  experiment  is  perfectly  successful  for  the 
near-by  observer,  it  is  necessary  to  consider  whether  it  will  be 
apparent  to  a  whole  class  in  a  large  room.  For  example,  the 


310  LECTURES  AND   RECITATIONS 

indications  of  a  gold-leaf  electroscope  are  very  likely  to  be  in- 
visible at  a  comparatively  short  distance,  because  of  the  light  of 
windows  reflected  from  the  surface  of  the  glass.  Shading  the 
windows,  lighting  the  electrometer  by  means  of  a  lamp  screened 
from  the  spectators,  and  using  white  paper  behind  the  instru- 
ment, makes  a  great  improvement. 

For  lecture-table  experiments  with  electric  currents  a  galvan- 
ometer with  vertical  index,  attached  to  a  needle  free  to  move 
in  a  vertical  plane,  is  extremely  useful.     Fortunately, 
Gaivano-          such  instruments  are  now  common  in  the  apparatus 
market. 

For  the  exhibition  of  weaker  currents,  requiring  the  use  of 
an  astatic  galvanometer  with  a  mirror,  I  have  found  the  device 
illustrated  by  the  following  figures  very  satisfactory.  In  Fig.  15 
(p.  311),  /  is  a  powerful  spiral  incandescent  lamp  (or  a  Wels- 
bach  burner),  within  an  opaque  vertical  cylinder,  E,  pierced  by 
a  small  orifice,  o,  through  which  light  goes  to  the  plane  galvan- 
ometer mirror,  m,  through  the  converging  lens,  c.  After  reflection 
from  m,  the  light  passes  through  the  plane  glass,  g,  to  a  second 
plane  mirror,/,  which  is  held  by  an  adjusting  screw,  a,  Fig.  16, 
passing  through  the  fixed  incline,  /,  at  such  an  angle  as  to  send 
the  light  to  the  scale,  s,  which  is  placed  some  feet  above  the 
galvanometer  and  is  inclined  about  45°  from  the  vertical.  The 
various  distances  are  such  that  an  image  of  o  is  formed  on  this 
screen,  and  this  image  can  easily  be  seen  by  a  large  class  in  a 
room  but  little  darkened.  The  envelope  E,  in  which  the  lamp 
is  placed,  should  be  open  at  top  and  bottom,  to  escape  over- 
heating, but  above  the  top  there  should  be  a  non-reflecting 
metal  screen  to  absorb  the  light  which,  if  not  arrested,  would 
reach  the  scale  on  which  the  image  of  o  is  shown. 

The  especial  merit  of  this  arrangement  of  lamp,  lens,  mirrors, 
etc.,  is  that  it  places  the  scale  directly  before  the  spectators, 
while  leaving  the  space  in  front  of  the  galvanometer  clear  for 
the  operations  of  the  lecturer. 

The  use  of  the  projecting  lantern  is  now  so  common,  and  is 
so  fully  described  by  the  publications  of  the  manufacturers,  that 


LECTURES  AND  RECITATIONS 


I  shall  not  dwell  upon  it.     "  Slides  "  sufficiently  good  for  cer- 
tain purposes,  tlie  exhibition  of  rough  diagrams,  for  example, 
can  be  made  without  the   use  of  photography  by   projecting 
merely  scratching  the  needful  lines  through  the  film 


Fig.J6. 


of  an  ordinary  photographic  plate.  For  extended  use  of  the 
lantern  the  usual  arrangement  of  putting  it  in  the  rear  of  the 
lecture-room,  the  screen  hanging  behind  the  lecture-table,  is 
probably  the  best ;  but  when  its  use  is  a  mere  incident  in  a 


312  LECTURES  AND   RECITATIONS 

lecture,  it  is  more  convenient  for  the  lecturer,  who  will  probably 
manage  the  lantern  himself,  to  have  it  on  the  lecture-table,  the 
screen  being  at  one  side  of  the  room. 

An  interesting  and  useful  device,  not  new  but  perhaps  un- 
familiar to  most  people,  has  for  its  object  the  projection  of  the 
image  of  any  flat  object  of  suitable  size  in  its  natural  colours. 
For  example,  a  picture  on  the  page  of  a  book  is  illuminated 
obliquely  by  means  of  the  condensing  lens  of  the  lantern,  and 
the  projecting  lens  of  the  lantern,  detached  from  its  usual  posi- 
tion, is  used  to  throw  the  image  of  the  picture  on  the  screen. 
Partitions  should  be  used  to  prevent  the  escape  of  too  much  of 
the  light  laterally. 

Opaque  roll  window-shades,  intended  for  thoroughly  darken- 
ing a  room,  are  troublesome  unless  carefully  made,  with  the 
Window-  edges  projecting  a  considerable  distance,  two  inches 
Shades.  iet  us  saVj  ]f  the  windows  are  large,  into  the  win- 

dow casing  on  each  side.  Without  this  precaution,  the  shades 
are  likely  to  bulge  inward  during  a  high  wind  and  draw  their 
edges  from  cover.  Such  shades  should  be  made  to  pull  down, 
like  ordinary  shades,  not  up,  lest  the  wear  and  tear  on  the  work- 
ing cords  be  too  great.  If  the  room  is  to  be  darkened  but  infre- 
quently, light,  portable,  wooden  frames  covered  with  oil-cloth, 
held  in  place  within  or  against  the  window  casings  by  any  simple 
fastening,  serve  well  enough. 

As  a  rule,  qualitative  experiments  are  given  to  better  advan- 
tage in  the  lecture-room,  as  quantitative  experiments  are  given 
Qualitative  to  better  advantage  in  the  laboratory ;  for  the  for- 
Experiments.  mer  nave  generally  a  spectacular  aspect,  often  suffi- 
ciently revealed  in  a  glance  at  the  critical  moment,  and  as  easily 
shown  to  many  spectators  as  to  one,  while  the  latter  are  more 
frequently  painstaking,  prolonged,  and  comparatively  unevent- 
ful, requiring  also  close  observation  at  short  range,  which  can- 
not be  given  by  the  whole  class  at  once. 

I  used  to  give  as  a  laboratory  exercise  a  study  of  the  phe- 
nomena occurring  in  the  heating  and  boiling  of  water,  and  had 
contrived  for  this  purpose  a  small-scale  piece  of  apparatus,  which 


LECTURES  AND  RECITATIC 


313 


could  easily  be  furnished  to  each  member  of  a  laboratory  sec- 
tion. But  after  some  years  of  trial  I  came  to  the  conclusion 
that  I  had  better  point  out  the  significant  features  of  the  pro- 
cess to  a  whole  class  at  once  than  to  each  member  of  the  class 
in  turn.  Accordingly,  I  now  show  the  experiment,  on  a  com- 
paratively large  scale,  in  the  lecture-room. 

Similarly,  I  used  to  have  each  student  or  each  pair  of  students 
go  through  certain  experiments  with  a  pressure-gauge  in  water, 
to  illustrate  or  discover  the  facts  that  pressure  increases  with 
depth,  is  independent  of  direction,  etc.  Now  I  do  not  insist 
upon  this,  but  show  these  experiments  to  groups  of  students  or 
to  a  whole  class  at  once.  A  little  contrivance  adapts  them  to 
the  projecting  lantern,  the  index  of  the  gauge  being  shown  on 
the  screen,  while  the  vessel  containing  the  water  is  in  direct 
view  of  the  spectators.  This  requires  the  gauge  to  be  fixed  at 
a  certain  height  and  the  water  in  which  it  is  submerged  to  be 
moved  up  and  down. 

It  is  well,  after  showing  important1  experiments  like  this  to  a 
class,  to  leave  the  apparatus  at  the  disposal  of  students,  who,  in 
the  laboratory,  may  wish  to  examine  it  at  short  range  or  to  use 
it  for  themselves. 


1  I  think  that  I  should  in  some  place,  here 
as  well  as  elsewhere,  object  to  that  device,  still 
to  be  seen  even  in  new  books,  which  undertakes 
to  prove  the  equality  of  vertical  and  horizontal 
pressure  at  a  given  depth  in  water  by  showing 
that  the  water  produces  the  same  effect  on  a 
vertical  mercury  column  when  admitted  to  the 
top  of  it  through  a  horizontal  tube,  as  when  ad- 
mitted through  a  vertical  tube.  See  a  and  b  of 
Fig.  17.  This  experiment  shows  that  the  verti- 
cal pressure  at  a  in  the  one  tube  is  equal  to 
the  vertical  pressure  at  6,  on  the  same  level, 
in  the  other  tube ;  but  to  say  that  the  vertical 
pressure  at  b  must  be  the  same  as  the  horizon- 
tal pressure  at  the  open  end  of  the  horizontal 
part  of  the  tube,  is  to  beg  the  whole  question 
at  issue. 


j 


r 


Fig,17. 


314  LECTURES  AND  RECITATIONS 

It  is  obvious  that  certain  matters  must  be  treated  by  lecture 
and  recitation  methods,  if  at  all,  for  the  reason  that  they  cannot 
Applications  be  brought  into  the  laboratory  and  put  at  the  dis- 
of  Physics.  posal  of  individual  pupils.  Such  are  large-scale  sys- 
tems of  heating,  ventilation,  drainage,  lighting,  transmission  of 
power,  etc.  These  should  be  presented  by  the  aid  of  diagrams 
and  verbal  explanations,  to  be  followed,  if  this  is  practicable 
under  good  conditions,  by  visits  to  the  apparatus  itself  in 
position  and  operation. 

It  is  a  question  how  much  instruction  on  such  topics  should 
be  undertaken,  and  this  question  must  be  answered  with  some 
reference  to  the  local  conditions  and  the  general  character  of 
the  school.  It  is  reasonable  that  all  boys,  at  least,  should 
acquire  a  good  general  understanding  of  ordinary  domestic 
scientific  appliances,  and,  in  their  simpler  forms,  of  the  steam- 
engine,  telegraph,  telephone,  dynamo,  and  motor;  but  it  is 
easily  possible  to  go  too  far  into  details.  I  can  give  no  better 
criterion  for  deciding  what  things  to  take  and  what  things  to 
leave  untouched,  than  that  which  is  furnished  by  the  interest  and 
probable  future  needs,  viewed  broadly,  of  the  ordinary  pupil. 
(See  Chapter  X.) 

The  immediate  aim,  though  not  the  sole  object,  of  instruc- 
tion in  physics  should  be  to  give  the  power  and  the  habit  of 
using  physical  knowledge.  It  should,  therefore,  on  the  side 
of  illustrations  and  applications,  be  suggestive  and  directive 
rather  than  exhaustive.  The  pupil  should  be  encouraged  to 
see  and  think  about  physical  phenomena  and  physical  devices 
which  are  outside  the  classroom ;  but  the  teacher  should  not 
be  expected  to  bring  all  such  things  to  his  attention  and  make 
him  understand  them. 

In  the  way  of  practical  applications  of  theory,  as  well  as  of 
theory  itself,  most  general  text-books  of  physics  contain  more, 
and  should  contain  more,  than  the  ordinary  class  can  be  ex- 
pected to  master  while  in  school.  The  teacher  should  not  be 
afraid  to  use  his  own  best  judgment,  and  omit  what  he  feels  to 
be  impracticable  or  comparatively  useless.  I  never  find  a 


LECTURES  AND  RECITATIONS  315 

general  text-book  of  which  I  can  require  a  class  to  take  every 
page.  The  fact  is,  of  course,  that  the  author  has  in  mind  a 
greater  variety  of  readers  than  is  found  in  any  one  class,  and  it 
is  generally  easier  for  the  teacher  to  skip  an  unnecessary  page 
than  to  supply  a  missing  one. 

Although  in  this  chapter  I  have  expressly  taken  it  for  granted 
that  the  teacher  will  see  the  need  of  thorough  preparation  for 
what  he  is  to  say  and  what  he  is  to  do  in  the  lecture-  care  for 
room,  it  may  be  worth  while  to  remark  that  such  Form- 
preparation  will  include  not  merely  the  parts  which  are  to  make 
up  the  teacher's  performance,  but  the  performance  as  a  whole. 
The  teacher  must  consider  not  only  what  to  say  and  what  to 
do,  but  when,  in  what  order,  each  thing  is  to  come.  He  must 
think,  too,  not  only  of  logical  sequence,  but  also  of  the  state  of 
mind  and  body  of  his  class,  following  no  single  line  of  thought 
too  long,  presenting  no  especially  difficult  matter  when  the 
class  is  tired. 

Physics  is,  at  the  best,  hard  for  most  minds,  young  or  older ; 
and  if  the  teacher  is  blessed  with  the  gift,  or  can  by  pains  acquire 
the  power,  of  presenting  his  subject  in  an  attractive  way,  of 
making  his  teaching  artistic  in  form  as  well  as  sound  in  sub- 
stance, he  will  win  not  only  the  respect  of  his  pupils  but,  what 
is  perhaps  to  both  sides  more  stimulating,  their  admiration. 


CHAPTER   IX 

PHYSICS   IN   PRIMARY   AND    GRAMMAR   SCHOOLS 

REFERENCES. 

Bailey,  J.  H.  Inductive  Physical  Science.  Boston,  D.  C.  Heath  & 
Co.  1896.  Pp.  105.  Qualitative  work. 

Cooley,  L.  R.  C.  Easy  Experiments  in  Physical  Science.  New  York, 
American  Book  Co.  Pp.  85.  Qualitative  work. 

Gifford,  J.  B.  Elementary  Lessons  in  Physics.  Boston,  Thompson, 
Brown  &  Co.  1894.  Pp.  161.  Largely  qualitative. 

Gregory,  R.  A.  and  Simmons,  A.  T.  Elementary  Physics  and  Chem- 
istry, First  Stage.  1899.  ^P-  I5°-  Elementary  Physics  and  Chemistry, 
Second  Stage.  1900.  Pp.  140.  London  and  New  York,  Macmillan. 

Harrington,  C.  L.  Physics  for  Grammar  Schools.  American  Book 
Co.  1897.  Pp.  123.  Largely  qualitative. 

Jackman,  W.  S.  Nature  Study  for  Grammar  Grades.  New  York, 
Macmillan.  1898.  Pp.  407.  A  book  of  suggested  experiments  (for 
teacher  or  pupil)  and  questions. 

Loewy,  B.  A  Graduated  Course  of  Natural  Science.  Parts  I.  and 
II.  London  and  New  York,  Macmillan  &  Co. 

I  AM  quite  in  sympathy  with  the  not  uncommon  practice  of 
giving  a  little,  a  very  little,  physics  of  a  descriptive  and  illus- 
"  Nature  trative  kind  to  young  children  as  a  part  of  what  is 
study."  often  called  "  nature  study."  But  as  I  have  never 

taught  physics  to  such  children  in  any  systematic  way,  and  am 
not  even  widely  read  in  the  literature  of  "  object  lessons,"  it  be- 
comes me  to  speak  with  caution  in  regard  to  such  teaching.  I 
shall  venture  the  suggestion,  however,  that  some  of  the  books  in 
which  these  lessons  are  set  forth  make  too  little  appeal  to  the 
experience  and  the  imagination  of  the  pupils. 

For  example,  from  an  English  book  which  has  much  to  be 
commended  of  instruction  in  regard  to  common  things,  I  take 
the  following  passages,  which  certainly  explain  themselves  : 


PRIMARY  AND  GRAMMAR  SCHOOLS        317 

"  Have  this  stone,  this  block  of  wood,  and  this  piece  of  iron 
any  shape  of  their  own  ?  Yes.  they  have,  and  we  cannot  alter 
the  shape  of  either  of  them.  Let  one  of  the  boys  take  the 
block  of  wood  in  his  hand,  and  another  the  piece  of  iron,  and 
try  to  squeeze  them  into  any  other  shape.  He  cannot  alter 
the  shape  of  either  the  wood  or  the  iron  with  all  his  pressing." 

"  Let  another  boy  try  with  the  stone." 

"  Now  put  the  stone,  or  the  wood,  or  the  iron  into  a  basin,  a 
tumbler,  or  some  such  vessel,  and  let  the  class  see  for  themselves 
that  these  substances  do  not  take  the  shape  of  the  vessel  in 
which  they  are  placed." 

I  find  it  difficult  to  believe  that  children  old  enough  to  go  to 
school  would  need  to  make  or  to  see  any  of  the  experiments 
here  described,  in  order  to  reach  the  desired  con-  f 

Cflild  s 

elusion  ;  and  it  is  bad  practice  to  ignore  the  vast  Experimental 

,    ,          ,  .  ,  .  .,  i    Knowledge. 

amount  of  knowledge  which  comes  to  every  child 

by  mere  virtue  of  his  living  and  having  his  five  senses, — 
knowledge  which  becomes  a  part  of  him,  is  blended  with  his 
natal  instincts,  long  before  he  can  read  and  write. 

No  small  part  of  the  difficulty  which  young  pupils  often  meet 
in  the  study  of  physics  is  difficulty  with  words,  due,  often, 
to  lack  of  simplicity  or  lack  of  precision  in  the  Ian-  ^  . 
guage  of  the  book  or  the  teacher.  For  example,  with 
what  pupil  is  ever  confused  as  to  the  fact  of  "  im- 
penetrability," and  what  pupil  is  not  confused  by  the  word?  I 
was  once  asked  by  a  grammar-school  teacher  what  I  thought  of 
a  certain  text-book  of  physics  which  he  was  using.  I  replied 
that  it  seemed  to  me  to  dwell  too  much  on  words  and  defini- 
tions. But  the  teacher  said  that  it  was  necessary  to  make  a  good 
deal  of  effort  to  get  down  to  the  comprehension  of  his  pupils. 
For  example,  he  had  lately  spent  many  minutes  in  trying  to  get 
his  class  to  understand  the  book  definition  of  uniform  velocity, 
which  ran  somewhat  as  follows  :  Uniform  velocity  is  such  a  rate 
of  motion  that  equal  distances  are  traversed  in  equal  successive 
intervals  of  time.  I  then  suggested  that  the  idea  of  uniform 
velocity  could  be  given  with  perfect  clearness  in  a  very  short 


318         PRIMARY  AND   GRAMMAR  SCHOOLS 

time  by  means  of  an  illustration,  and  that  the  analysis  and  mas- 
tery of  such  a  definition  as  he  had  been  using,  though  it  might 
be  highly  profitable  to  the  pupils  as  an  exercise  in  language, 
was  not  the  study  of  physics.  This  the  teacher  admitted,  but 
he  held  that  such  language  lessons  are  a  legitimate  use  of  the 
time  assigned  to  physics  in  a  grammar  school. 

This  teacher's  view  may  be  right,  but  let  us,  at  least,  locate 
the  difficulty  properly,  and  not  condemn  the  study  of  physics 
as  too  hard  for  grammar  schools,  merely  because  many  of  its 
simpler  truths  are  often,  unnecessarily,  expressed  too  abstrusely. 
Why  could  we  not  say,  Uniform  velocity  is  velocity  that  is 
unchanging,  neither  growing  greater  nor  growing  less  1 

The  habit  of  overlaboured  expression,  on  which  I  have  been 
commenting,  is  often  the  result  of  a  commendable  desire  to 
LackofPre-  escape  a  still  worse  fault,  the  habit  of  indefinite- 
cision.  ness,  lack  of  precision  of  speech  and  meaning.  I 

have  known  a  class  to  spend  nearly  an  hour  on  an  elementary 
exercise,  leading  up  to  the  hydrostatic  press,  without  any 
general  understanding  as  to  whether  the  word  size,  as  used 
with  regard  to  the  tubes  employed  in  the  experiment,  meant 
diameter  or  area  of  cross-section. 

An  interesting  and  important  question  is,  whether  the  study 
of  physics  by  young  pupils  should  be  mainly  qualitative  or 
Qualitative  or  mainly  quantitative,  that  is,  whether  it  should  be 
Quantitative?  devoted  mainly  to  the  development  and  illustra- 
tion of  important  phenomena,  or  mainly  to  the  study  of 
numerical  laws  relating  to  such  phenomena.  In  my  opinion, 
the  little  physics  taught  in  primary  schools  or  in  the  lower 
grades  of  grammar  schools,  should  be  mostly  or  wholly  of 
the  lecture-table  sort,  and  qualitative.  But  as  soon  as  the 
formal  study  is  begun,  with  laboratory  work  by  the  pupils,  I 
am  clear  that  the  work  should  be,  I  had  almost  said  must 
be,  chiefly  quantitative.  It  is  so  difficult  to  design  a  course 
of  laboratory  experiments  which  will  lead  the  pupil  to  dis- 
cover or  observe,  in  any  general  way,  phenomena  not  pre- 
viously known  to  him,  so  difficult,  therefore,  to  prevent 


PRIMARY  AND   GRAMMAR  SCHOOLS        319 

qualitative  laboratory  work  from  becoming  a  farce  and  a  bore, 
in  which  the  wearied  teacher  points  out  to  each  pupil  the 
thing  which  the  latter  is  supposed  to  discover,  that  I  have 
long  considered  the  undertaking  unprofitable.  Of  course  it 
is  easy  to  write  out  a  long  list  of  questions,  most  excellent 
if  the  pupil  could  find  the  answers  to  them,  leaving  it  for  the 
teacher  to  make  the  apparatus  and  devise  all  details ;  but  how 
much  is  really  accomplished  by  such  imposing  suggestions  ? 

It  is  true  that  writers  of  great  ingenuity  have  undertaken  to 
lay  out  practical  courses  of  qualitative  work,  and  that  some 
teachers  of  great  zeal  are  following  more  or  less  closely  the 
courses  which  they  have  described  ;  but  I  get  from  their  work, 
so  far  as  I  am  familiar  with  it,  at  times  the  impression  of 
tremendous  "inductive"  feats,  surpassing  the  intuitions  of 
Newton,  and  at  others  the  impression  of  an  effort  rather  to 
occupy  the  pupil  as  long  as  possible  with  certain  simple  pieces 
of  apparatus  than  to  teach  him  as  much  as  possible  in  a  given 
time.  The  latter  practice  reminds  one  of  a  box  of  puzzle 
blocks  with  a  chart  of  the  figures  which,  with  sufficient  ingenu- 
ity and  time,  can  be  constructed  from  them.  Puzzle  blocks 
are  very  good  indeed  in  their  way,  and  I  am  far  from  asserting 
that  the  kind  of  laboratory  work  which  I  have  compared  to 
their  use  is  profitless.  It  does,  no  doubt,  give  some  manipu- 
lative skill,  and  it  gives  some  practice  in  keeping  a  record  of 
observations,  but,  as  a  means  of  getting  forward  with  the  study 
of  physics,  I  believe  that  it  can  be  greatly  improved  upon. 

The  practice  of  dwelling  unnecessarily  long  on  things  familiar 
and  essentially  simple,  of  discussing  them  at  great  length  and 
laboriously  writing  out  observations  upon  them,  is  Too  Slow 
a  vicious  one ;  for  it  inculcates  a  habit  of  potter-  ^ogress. 
ing,  and  is  quite  as  likely  to  result  in  confusion  of  ideas  as  in 
lucidity.     The  fact  that  a  pupil  cannot  give  a  clear  account  of 
some  particular  fact  or  law  is  no  sure  proof  that  he  has  not 
spent  too  much  time  on  it.     It  is  possible  to  gaze  at  one's 
own  name  until  it  looks  unfamiliar  and  weird. 

Movement,  a  certain  sense  of  progress,  is  essential  to  the 


320        PRIMARY  AND  GRAMMAR  SCHOOLS 

best  working  of  the  pupil's  mind,  which,  like  a  bicycle,  simply 
lies  down  if  it  is  kept  too  long  in  one  spot.  It  is  better  to 
maintain  this  progress,  even  with  the  certainty  that  some  things 
will  be  passed  by  unseen,  and  that  many  of  the  things  seen 
will  be  forgotten,  than  to  lose  headway  and  the  alertness  which 
goes  with  it.  Many  repetitions  are  necessary  for  the  mastery 
of  certain  truths ;  but  these  repetitions  should  not  all  come  at 
one  stretch.  An  occasional  brief  return  to  the  difficult  point, 
when  the  mind  is  fresh,  is  better  in  many  cases  than  the 
attempt  to  level  every  obstacle  and  clear  up  every  doubt  at 
the  first  progress. 

Quantitative  Laboratory  Work  in  Grammar  Schools. 

For  eight  or  nine  years  now  the  grammar  schools  of  Cam- 
bridge, Massachusetts,  have  maintained  a  course  of  quantita- 
Exercises  ^ve  laboratory  work  for  pupils  of  the  ninth  grade, 
Taken.  averaging  perhaps  fourteen  years  of  age.  The  titles 

of  the  exercises  in  this  course  are,  for  the  most  part,  such  as 
are  to  be  found  in  the  First  Part  of  the  Harvard  Descriptive 
List  or  the  corresponding  list  of  the  National  Educational 
Association  (see  Chapter  X.)  ;  and  the  method  of  perform- 
ance of  these  exercises  follows  pretty  closely  the  directions 
given  in  the  Descriptive  List.  The  pupils,  however,  do  not 
have  these  or  any  printed  directions  before  them  in  doing 
their  work,  nor  have  they,  in  fact,  any  text-book  of  physics. 

Apparently  the  teachers  prefer  not  to  have  a  book  in  the 
hands  of  the  pupils.  The  time  allowed  for  the  whole  course 

is  only  two  school  periods,  of  40  minutes  each,  a 
Wo  Text-book.  .    *  j      t_     •       • 

week  for   one  school  year,  and  physics  is   treated 

as  one  of  the  minor  studies  of  the  grammar  school  course. 
Under  these  conditions  the  teachers  apparently  feel  that  it  is 
hardly  worth  while  to  take  up  a  text-book,  some  parts  of  which 
might  be  too  difficult  or  too  laborious  for  their  pupils.  I 
think,  too,  that  they  find  a  certain  legitimate  satisfaction  in 
lecturing  to  their  classes  in  this  study,  which  is  more  objective 
than  most  others  with  which  they  have  to  do. 


PRIMARY  AND  GRAMMAR  SCHOOLS         321 

It  must  be  admitted  that  when  these  Cambridge  pupils, 
after  dropping  the  study  of  physics  entirely  for  two  years,  re- 
sume it  in  the  third  year  of  the  high  school  course,  permanence 
there  is  generally  not  very  much  immediately  of  Results? 
visible  in  their  minds. as  the  result  of  their  previous  work  in 
this  subject.  But  in  what  study  will  the  direct  product  of  two 
school  periods  per  week  for  one  grammar  school  year  show 
to  great  advantage  two  years  later?  Arithmetic,  geography, 
history?  In  no  study  that  can  be  named,  unless  circumstances 
are  such  as  to  keep  the  lessons  of  that  study  frequently  in 
practice. 

Many  of  the  things  learned  by  a  boy  in  such  a  course  of 
physics  as  that  indicated  above,  will  go  into  frequent  practice  in 
his  e very-day  life.  He  will,  therefore,  probably  remember  his 
physics  as  well  as  he  remembers  anything  on  which  so  little  time 
has  been  spent.  It  will  be  best,  if  not  necessary,  to  go  all  over 
the  same  ground  again  in  the  high  school ;  but  that  is  no  proof 
whatever  that  the  first  study  has  not  been  profitable.  Such 
preliminary  study  is  like  the  coat  of  oil  which  is  laid  on  wood 
to  prepare  it  for  varnishing.  The  oil  dries  in  and  disappears, 
but  the  varnish,  the  show  coat,  sticks  because  the  oil  has  gone 
before  it. 

But  the  question  remains,  whether  such  work  had  better  be 
done  by  a  grammar  school  class.  There  is  a  chance  for  mis- 
understanding here.  The  question  is  not,  whether  the  same 
list  of  experiments  done  later  will  teach  more,  for  it  must  be 
granted  that  almost  any  study  pursued  at  the  grammar  school 
age  would  yield  larger  results  with  an  equal  expenditure  of  time 
two  or  three  years  later.  The  question  is,  whether  this  course, 
or  some  such  course,  of  physics  is  more  profitable  to  the  class 
as  a  whole  than  anything  which  could,  or  would,  take  its  place. 

I  am,  possibly,  too  much  influenced  by  the  circumstances  of 
the  case  to  give  this  question  a  judicial  answer.  If  all  the 
pupils  were  to  go  forward  into  a  higher  school,  I  should  perhaps 
answer  it  in  the  negative  ;  but  a  comparatively  small  propor- 
tion of  them  do  this.  Is  it  wise,  is  it  fair,  to  let  the  great 


322         PRIMARY  AND   GRAMMAR  SCHOOLS 

majority  of  public-school  children  close  their  school  life  without 
any  formal  study  of  natural  science  ?  Are  school  authorities 
sufficiently  sure,  for  example,  of  the  superior  profitableness  of 
the  back  part  of  the  arithmetic,  partial  payments,  etc.,  to  war- 
rant them  in  preserving  all  its  commercial  features  to  the  exclu- 
sion of  natural  science  ? 

The  following  paragraphs  are  written  by  Mr.  Frederick  S. 
Cutter,  the  master  of  the  Peabody  Grammar  School  of 
Cambridge  : 

"  The  time  allotted  to  the  subject  [of  physics]  is  one  hour  and 
twenty  minutes  a  week  throughout  the  school  year,  of  which 
thirty  minutes  is  for  laboratory  work  and  fifty  minutes  for  dis- 
cussion and  lecture-table  instruction  in  the  classroom.  The 
class  is  divided  [for  laboratory  work]  into  sections  of  sixteen 
(or  less)  pupils  each." 

"  Time  for  the  introduction  of  physics,  and  also  geometry, 
was  obtained  in  the  revision  of  the  course  of  study  by  complet- 
Commentsby  ing  the  subJect  of  geography  in  the  eighth  grade 
School-  and  by  modifying  the  requirements  in  arithmetic. 

The  one  hour  and  twenty  minutes  a  week  devoted 
to  physics  is  supplemented  by  a  part  of  the  time  assigned  to 
language  work,  when  written  compositions  are  prepared  by  the 
pupils  in  which  accounts  of  their  experiments  are  given  from 
the  notes  taken  in  the  laboratory.  These  compositions  are 
usually  illustrated,  for  children  as  a  rule  like  to  write  about 
what  they  have  performed,  and  take  pleasure  in  the  adornment 
of  their  papers.  Thus  the  subjects  of  physics,  language,  and 
drawing  are  most  profitably  correlated. 

"Before  the  introduction  of  laboratory  physics  there  were 
some  who  feared  that  a  serious  difficulty  would  be  the  time  and 
labour  required  of  the  teacher  in  preparation  for  an  experiment 
to  be  performed  by  sixteen  children,  and  afterwards  in  putting 
the  things  away.  But  in  practice  it  is  found  that  the  teacher 
can  be  largely  relieved  by  several  of  the  most  trustworthy  pupils, 
who  are  always  glad  to  offer  their  services  as  assistants.  To 
one  can  be  given  entire  charge  of  the  sixteen  large  glass  jars, 


PRIMARY  AND   GRAMMAR  SCHOOLS        323 

the  filling,  the  emptying,  and  the  putting  away  in  proper  condi- 
tion ;  to  another  can  be  given  the  care  of  the  sixteen  overflow 
cans  ;  to  another  the  care  of  the  spring-balances,  etc.  The 
children  selected  will  profit  by  the  responsibility  they  assume, 
and  will  take  increased  interest  in  the  work,  their  influence 
being  favourably  felt  throughout  the  class.  If  the  teacher 
announces  in  the  morning  session  what  will  be  needed  for  the 
experiment  in  the  afternoon,  the  pupils  can  get  everything  in 
readiness  during  the  noon  intermission." 


CHAPTER  X 

PHYSICS  IN  VARIOUS  KINDS   OF  SECONDARY  SCHOOLS 

REFERENCES. 

Laboratory  Manuals : 

Manuals  included  in  text-books  and  not  published  separately  are  not 
here  named. 

Adams,  C.  F.  Physical  Laboratory  Manual  for  Secondary  Schools. 
Chicago  &  New  York,  Werner  School  Book  Co.  1896.  Pp.  183. 

Allen,  C.  R.  Laboratory  Exercises  in  Elementary  Physics.  New 
York,  Henry  Holt  &  Co.  1892.  Pp.  277. 

Ames,  J.  S.  and  Bliss,  W.  J.  A.  Manual  of  Experiments  in  Physics. 
American  Book  Co.  1898.  Pp.  544. 

Ayres,  F.  H.  Laboratory  Exercises  in  Elementary  Physics.  London, 
E.  Arnold.  New  York,  D.  Appleton  &  Co.  1901.  Pp.  193.  To  accom- 
pany Henderson  and  Woodhull's  Elements  of  Physics. 

Chute,  H.  N.  Physical  Laboratory  Manual.  London,  Isbister  &  Co. 
Boston,  D.  C.  Heath  &  Co.  1894.  Pp.  218. 

Crew,  H.  and  Tatnall.  Laboratory  Manual  of  Physics.  London  and 
New  York,  Macmillan.  1902.  Pp.  234. 

Gage,  A.  P.     Physical   Experiments.     Boston,    Ginn   &   Co.     1897. 

Pp.  195- 

Gage,  A.  P.  Physical  Laboratory  Manual  and  Note-book.  1890. 
Pp.  244.  Boston,  Ginn  &  Co. 

Glazebrook,  R.  T.  and  Shaw,  "W.  N.  Practical  Physics.  London  and 
New  York,  Longmans,  Green  &  Co.  New  Edition,  1901.  Pp.  659.  Too 
difficult  for  school  use. 

Henderson,  John.  Elementary  Physics.  London  and  New  York, 
Longmans,  Green  &  Co.  1895.  Pp.  132.  For  colleges  rather  than 
schools. 

Henderson,  C.  H.  and  Woodhull,  J.  F.  Physical  Experiments.  New 
York,  Appleton  &  Co.  1900.  Pp.  112.  To  accompany  the  Authors' 
Elements  of  Physics  and  sometimes  bound  with  the  Elements. 

Hopkins,  W.  J.  Preparatory  Physics.  Longmans,  Green  &  Co.  1894. 
Pp.  147. 

Hortvet,  J.  A  Manual  of  Elementary  Practical  Physics  for  High 
Schools.  Minneapolis,  H.  W.  Wilson. 

Kelsey,  W.  R.  Physical  Determinations.  London,  Arnold.  New 
York,  Longmans,  Green  &  Co.  1901.  Pp.  328. 


VARIOUS  KINDS  OF  SECONDARY  SCHOOLS     325 

Nichols,  Smith  and  Turton.  Manual  of  Experimental  Physics.  Bos- 
ton, Ginn  &  Co.  1899.  Pp.  324. 

Rintoul,  D.  An  Introduction  to  Practical  Physics.  London  and  New 
York,  Macmillan.  1898.  Pp.  166.  Mensuration,  Mechanics,  and  Heat. 
Schuster,  A.  and  Lees,  C.  H.  Intermediate  Course  in  Practical  Phy- 
sics. London  and  New  York,  Macmillan  &  Co.  1896.  Pp.  248.  De- 
scribes a  course  given  in  Owens  College. 

Stewart,  B.  and  Gee,  W.  W.  H.  Elementary  Practical  Physics. 
Vol.  I.  General  Processes.  1893.  PP-  295-  Vol<  JI-  Electricity  and 
Magnetism.  1896.  Pp.  503.  Vol.  III.  Practical  Acoustics  (by  C.  L. 
Barnes).  1897.  Pp.  214.  London  and  New  York,  Macmillan  &  Co. 
Rather  beyond  school  class  use. 

Stratton.  Outline  of  a  Course  in  General  Physics  for  Secondary 
Schools.  SCHOOL  REVIEW.  January,  1898.  7  pages. 

Watson,  Wm.  Elementary  Practical  Physics.  A  Laboratory  Manual 
for  Beginners.  London  and  New  York,  Longmans,  Green  &  Co.  1896. 
Pp.  238. 

Woodhull,  J.  F.  First  Course  in  Science.  Vol.  I.  Book  of  Experi- 
ments. Henry  Holt  &  Co.  1893.  Pp.  79.  Light  only.  Vol.  II.  is  a 
text-book  to  accompany  the  manual.  Pp.  133. 

Worthington,  A.  M.  Physical  Laboratory  Practice.  London,  Long- 
mans, Green  &  Co. 

General  Text-books,  Mainly  for  Teachers'  Use  : 

Anthony,  W.  A.  and  Bracket,  C.  F.  Elementary  Text-book  of  Phy- 
sics. Revised  by  Magie.  New  York,  John  Wiley  &  Sons.  1897. 
Pp.  512. 

Barker,  G.  F.  Physics.  Advanced  Course.  London,  Macmillan  & 
Co.  New  York,  Henry  Holt  &  Co.  1892.  Pp.  902. 

Daguin,  P.  A.  Traite  Elementaire  de  Physique.  Paris.  3  vols. 
Contains  much  descriptive  and  historical  matter. 

Daniell,  A.  A  Text-book  of  Physics.  London  and  New  York,  Mac- 
millan &  Co.  1895.  PP-  782- 

Deschanel,  A.  P.  Natural  Philosophy.  Translated  and  revised  by 
Everett.  London,  Blackie  &  Son.  New  York,  D.  Appleton  &  Co. 
4  vols.  The  3d  vol.,  Electricity  and  Magnetism,  issued  in  1901. 

Ganot's  Physics.  Translated  and  edited  by  E.  Atkinson.  London, 
Longmans,  Green  &  Co.  New  York.  Wm.  Wood  &  Co.  Pp.  1115. 

Ganot's  Popular  Natural  Philosophy.  Translated  and  edited  by  E. 
Atkinson.  Longmans,  Green  £  Co.  1900.  Pp.  752. 

Hastings,  C.  S.  and  Beach,  F.  E.  Text-book  of  General  Physics. 
Boston,  Ginn  &  Co.  Pp.  768. 

Lehfeldt,  R.  A.  A  Text-book  of  Physics,  with  Sections  on  the  Appli- 
cations of  Physics  to  Physiology  and  Medicine.  London,  Arnold.  New 
York,  Longmans,  Green  &  Co.  1902.  Pp.  312. 

Nichols,  E.  L.  and  Franklin,  W.  S.  Elements  of  Physics.  Vol.  I. 
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326      VARIOUS  KINDS  OF  SECONDARY  SCHOOLS 

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Watson,  Wm.  A.  Text-book  of  Physics.  London  and  New  York, 
Longmans,  Green  &  Co.  1899.  Pp.  896. 

Special  Treatises,  Mainly  for  Teachers'1  Use : 

Abney,  W.  D.  W.  Treatise  on  Photography  (Text-books  of  Science). 
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Benjamin,  P.  A  History  of  Electricity.  New  York,  John  Wiley  & 
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Goodeve,  T.  M.  Text-book  on  The  Steam  Engine  and  on  Gas  Engines. 
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Halliday,  G.  Steam  Boilers.  London,  Edward  Arnold.  New  York, 
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Hardin,  W.  L.  Liquefaction  of  Gases.  London  and  New  York, 
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Harrington,  M.  W.  About  the  Weather.  (Home  Reading  Books.) 
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Holden,  E.  S.  Stories  of  the  Great  Astronomers.  1901.  Pp.  255. 
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New  York,  D.  Appleton  &  Co. 

Hopkins,  W.  J.  Telephone  Lines  and  Their  Properties.  1886. 
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Jackson,  D.  C.  and  J.  P.  Alternating  Current  and  Alternating  Cur- 
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Jones,  H.  C.  Theory  of  Electrolytic  Dissociation.  London  and  New 
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1896.  Pp.  284. 

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Pp.  348. 

Preeca,  W.  H.  and  Sivewright,  J.  Telegraphy.  London  and  New 
York,  Longmans,  Green  &  Co.  1897.  Pp.  417. 

Preston,  T.  The  Theory  of  Heat.  1894.  Pp.  719.  The  Theory  of 
Light.  1901.  Pp.  586.  London  and  New  York,  Macmillan. 


VARIOUS  KINDS  OF  SECONDARY  SCHOOLS     327 

Shelley,  C.  P.  B.  Work-Shop  Appliances.  London  and  New  York, 
Longmans,  Green  &  Co.  1897.  Pp.  377. 

Shenstone,  W.  A.  The  Methods  of  Glass-Blowing.  London  and  New 
York,  Longmans,  Green  &  Co.  New  ed.,  1902.  Pp.  86. 

Slingo,  W.  and  Brooker,  A.  Electrical  Engineering  for  Electric 
Light  Artisans  and  Students.  London  and  New  York,  Longmans,  Green 
&  Co.  1898.  Pp.  780. 

Stretton,  C.  E.  The  Locomotive  and  Its  Development.  London,  C. 
Lockwood  &  Sons. 

Thompson,  S.  P.  Elementary  Lessons  in  Electricity  and  Magnetism. 
1894.  Pp.  638.  Light  Visible  and  Invisible.  1897.  Pp.  294.  London 
and  New  York,  Macmillan. 

Treadwell,  A.  The  Storage  Battery.  London,  Whittaker  &  Co. 
New  York,  Macmillan  &  Co.  1898.  Pp.  257. 

Whetharn,  W.  C.  D.  Solution  and  Electrolysis.  Cambridge,  Uni- 
versity Press.  New  York,  Macmillan.  1895.  ^P'  29^- 

Wilson,  E.  Electrical  Traction.  London,  Edward  Arnold.  New 
York,  Longmans,  Green  &  Co.  1897.  Pp.  253. 

"Wright,  M.  R.  Sound,  Light,  and  Heat.  Pp.  272.  Heat.  Pp.  346. 
London  and  New  York,  Longmans,  Green  &  Co. 

Yorke,  J.  P.  Magnetism  and  Electricity.  London,  Edward  Arnold. 
New  York,  Longmans,  Green  &  Co.  1899  Pp.  264. 

ON  the  subject  of  this  chapter  we  have  something  approach- 
ing the  authority  of  official  utterance  in  the  various  publications 
made  by  the  National  Educational  Association  during  the  past 
ten  or  twelve  years. 

College  Entrance  Physics  of  the  National  Educational  Association. 

The  general  definition  or  description  of  the  type  of  physics 
course,    preparatory   for   college,    which   is    approved    by   the 
National  Educational  Association,  is  shown  by  the 
following  extract  from  the  report  of  its  committee   Recommen- 
on   College   Entrance  Requirements,  which  report 
was  published  in  1899  by  the  authority  of  the  association. 

"Your  committee  suggests  that  an  effective  working  basis 
for  a  secondary  school  course  in  physics  would  be  attained  by 
planning  such  a  course  substantially  in  accordance  with  the 
following  propositions : 

"  i.  That  in  public  high  schools  and  schools  preparatory  for 
college  physics  be  taught  in  a  course  occupying  not  less  than 


328       VARIOUS  KINDS  OF  SECONDARY  SCHOOLS 

one  year  of  daily  exercises,  more  than  this  amount  of  time  to 
be  taken  for  the  work  if  it  is  begun  earlier  than  the  next  to  the 
last  year  of  the  school  course. 

"2.  That  this  course  of  physics  include  a  large  amount  of 
laboratory  work,  mainly  quantitative,  done  by  the  pupils  under 
the  careful  direction  of  a  competent  instructor  and  recorded  by 
the  pupil  in  a  note-book. 

"3.  That  such  laboratory  work,  including  the  keeping  of  a 
note-book  and  the  working  out  of  results  from  laboratory  obser- 
vations, occupy  approximately  one-half  of  the  whole  time  given 
to  physics  by  the  pupil. 

"4.  That  the  course  also  include  instruction  by  text-book 
and  lecture,  with  qualitative  experiments  by  the  instructor, 
elucidating  and  enforcing  the  laboratory  work,  or  dealing  with 
matters  not  touched  upon  in  that  work,  to  the  end  that  the 
pupil  may  gain  not  merely  empirical  knowledge,,  but,  so  far  as 
this  may  be  practicable,  a  comprehensive  and  connected  view 
of  the  most  important  facts  and  laws  in  elementary  physics. 

"5.  That  college-admission  requirements  be  so  framed  that  a 
pupil  who  has  successfully  followed  out  such  a  course  of  physics 
as  that  here  described  may  offer  it  toward  satisfying  such  re- 
quirements." l 

The  report  from  which  the  preceding  extract  is  taken  was 
approved  in  the  year  following  its  publication,  in  the  following 
Histor  of  resolution  :  "  Resolved,  That  the  Departments  of 
theW.E.A.  Secondary  and  Higher  Education  of  the  National 
Educational  Association  commend  the  report  of 
the  special  Committee  on  College-Entrance  Requirements  as 
offering  a  basis  for  the  practical  solution  of  the  problems  of 
college  admission,  and  recommend  the  report  to  the  colleges 
of  the  country." 

The  report  under  discussion  consisted  of  two  parts,  a  shorter 
part,  for  which  the  committee  itself  took  the  responsibility,  and 

1  These  five  propositions  are  substantially  a  repetition  of  recommenda- 
tions made  to  the  General  Committee  by  the  Committee  on  Physics, 
the  membership  of  which  is  given  later. 


VARIOUS  KINDS  OF  SECONDARY  SCHOOLS     329 

from  which  the  extract  above  given  is  taken,  and  a  longer  part 
containing  many  details  offered  in  the  reports  of  various  sub- 
committees. In  this  supplementary  part  of  the  report  the 
matter  relating  to  physics,  quoted  in  full  below,  is  little  more 
than  the  Table  of  Contents  of  the  Harvard  Descriptive  List 
(see  Chapter  V.)  and  two  paragraphs  taken,  almost  without 
change,  from  the  Introduction  to  that  list.  As  this  fact  is 
capable  of  misinterpretation  by  those  not  fully  acquainted 
with  the  circumstances,  I  shall  give  some  account  of  the 
matter  here. 

As  chairman  of  the  committee  mentioned  in  the  quotation 
following,  I  had  reported  to  Dr.  Nightingale,  the  chairman  of 
the  general  Committee  on  College  Entrance  Requirements, 
that,  inasmuch  as  the  Physics  Committee  was  made  up  largely 
of  gentlemen  who  had  written  text-books  —  very  different  text- 
books—  for  schools,  or  were  in  the  way  of  writing  such  books, 
I  could  not  undertake  to  get  from  them  any  general  agreement 
as  to  the  details  of  what  a  course  in  schools  should  be.  But, 
as  Dr.  Nightingale  insisted  on  some  kind  of  a  report  on  this 
subject,  I  at  last  sent  him  what  is  practically  a  description  of 
the  Harvard  requirement  in  laboratory  work,  as  my  individual 
report,  at  the  same  time  notifying  the  other  members  of  the 
committee  of  what  I  had  done,  and  requesting  each  of  them  to 
take  corresponding  individual  action,  if  he  felt  moved  to  do  so. 
The  quotations  which  follow  show  the  result. 

"  The  Committee  on  Physics  of  the  Science  Department  of 
the  National  Educational  Association  did  not  submit  a  regular 
report  signed  by  the  members  of  the  committee. 
These  were:  Professor  E.  H.  Hall,  Harvard  Uni- 

versity,  chairman ;  Professor  H.   S.   Carhart,  Uni-  Physlcs 

Cemmittee. 
versity  of  Michigan,    Ann   Arbor ;   R.   B.   Fulton, 

Chancellor,  University  of  Mississippi ;  C.  L.  Harrington,  Sachs' 
Collegiate  Institute,  New  York,  N.  Y. ;  Julius  Hortvet,  East 
Side  High  School,  Minneapolis,  Minn. ;  C.  J.  Ling,  Manual 
Training  School,  Denver,  Colo. ;  Professor  E.  L.  Nichols, 
Cornell  University,  Ithaca,  N.  Y. ;  E.  D.  Pierce,  Hotchkiss 


330       VARIOUS  KINDS   OF  SECONDARY  SCHOOLS 

School,  Lakeville,  Conn. ;  Professor  Fernando  Sanford,  Leland 
Stanford,  Jr.,  University,  Cal. ;  Professor  B.  F.  Thomas,  Ohio 
State  University,  Columbus;  Edward  R.  Robbins,  Lawrence- 
ville  School,  Lawrenceville,  N.  J. 

"The  basis  of  a  report,  suggested  by  Professor  Hall,  and 
consisting  of  a  list  of  laboratory  experiments,  is  given  below. 
Comments  by  the  members  of  the  committee,  in  case  they  dis- 
sented from  any  part  of  this,  were  to  be  sent  at  once  to  the 
chairman  of  the  Committee  on  College-Entrance  Requirements. 
It  may  be  assumed  that  the  list  met  with  the  approval  of  those 
who  did  not  so  indicate  dissent.  Such  comments  as  have  been 
received  are  given  after  Professor  Hall's  statement. 

"  Outline  of  Laboratory  Work  in  Physics  for  Secondary  Schools. 

"  At  least  thirty-five  exercises,  selected  from  a  list  of  sixty  or 

more,  not  very  different  from  the  list  given  below.     In  this  list 

the  divisions  are  mechanics  (including  hydrostatics), 

List  of  light,  heat,  sound,  and  electricity  (with  magnetism). 

At  least  ten  of  the  exercises  selected  should  be  in 

mechanics.    The  exercises  in  sound  may  be  omitted  altogether ; 

but  each  of  the  three  remaining  divisions  should  be  represented 

by  at  least  three  exercises. 

"  The  division  of  the  list  into  a  first  part  and  a  second  part 
is  intended  to  facilitate  and  encourage  beginning  the  study  of 
physics  very  early  in  the  school  course.  Most  of  the  exercises 
in  the  first  part  have  proved  to  be  within  the  power  of  boys  of 
fourteen  or  fifteen  years,  although  older  pupils  can  do  them 
more  readily,  as  they  can  do  all  other  work  except  tasks  of 
pure  memory.  The  cost  of  apparatus  for  the  exercises  of  the 
first  part  is  very  small. 

"  First  Part. 
PRELIMINARY  EXERCISES. 

[Recommended,  but  not  to  be  counted.] 

A.  Measurement  of  a  straight  line. 

B.  Lines  of  the  right  triangle  and  the  circle. 


VARIOUS  KINDS  OF  SECONDARY  SCHOOLS     33  I 

C.  Area  of  an  oblique  parallelogram. 

D.  Volume  of  a  rectangular  body  by  displacement  of  water. 

MECHANICS  AND  HYDROSTATICS. 

1.  Weight  of  unit  volume  of£  substance. 

2.  Lifting  effect  of  water  upon  a  body  entirely  immersed  in  it. 

3.  Specific  gravity  of  a  solid  body  that  will  sink  in  water. 

4.  Specific  gravity  of  a  block  of  wood  by  use  of  a  sinker. 

5.  Weight  of  water  displaced  by  a  floating  body. 

6.  Specific  gravity  by  flotation  method. 

7.  Specific  gravity  of  a  liquid  :  two  methods. 

8.  The  straight  lever  :  first  class. 

9.  Centre  of  gravity  and  weight  of  a  lever. 
10.  Levers  of  the  second  and  third  classes. 
IT.  Force  exerted  at  the  fulcrum  of  a  lever. 

1 2.  Errors  of  a  spring  balance. 

13.  Parallelogram  of  forces. 

14.  Friction  between  solid  bodies  (on  a  level). 

15.  Coefficient  of  friction  (by  sliding  on  incline). 

LIGHT. 

1 6.  Use  of  Rumford  photometer. 

1 7.  Images  in  a  plane  mirror. 

18.  Images  formed  by  a  convex  cylindrical  mirror. 

19.  Images  formed  by  a  concave  cylindrical  mirror. 

20.  Index  of  refraction  of  glass. 

21.  Index  of  refraction  of  water. 

22.  Focal  length  of  a  converging  lens. 

23.  Conjugate  foci  of  a  lens. 

24.  Shape  and  size  of  a  real  image  formed  by  a  lens. 

25.  Virtual  image  formed  by  a  lens. 

Second  Part. 

MECHANICS. 

26.  Breaking  strength  of  a  wire. 

27.  Comparison  of  wires  in  breaking  tests. 


332      VARIOUS  KINDS   OF  SECONDARY  SCHOOLS 

28.  Elasticity :  stretching. 

29.  Elasticity  :  bending  ;  effects  of  varying  loads. 

30.  Elasticity:  bending;   effects  of  varying  dimensions. 

31.  Elasticity:  twisting. 

32.  Specific  gravity  of  a  liquid  by  balancing  columns. 

33.  Compressibility  of  air :  Boyle's  law. 

34.  Density  of  air. 

35.  Four  forces  at  right  angles  in  one  plane. 
30.  Comparison  of  masses  by  acceleration  test. 

37.  Action  and  reaction:  elastic  collision. 

38.  Elastic  collision  continued  :  inelastic  collision. 

HEAT. 

39.  Testing  a  mercury  thermometer. 

40.  Linear  expansion  of  a  solid. 

41.  Increase    of    pressure   of    a    gas    heated    at    constant 

volume. 

42.  Increase  of  volume  of  a  gas  heated  at  constant  pressure. 

43.  Specific  heat  of  a  solid. 

44.  Latent  heat  of  melting. 

45.  Determination  of  the  dew-point. 

46.  Latent  heat  of  vaporization. 

SOUND. 

47.  Velocity  of  sound  in  open  air. 

48.  Wave-length  of  sound. 

49.  Number  of  vibrations  of  a  tuning  fork. 

ELECTRICITY  AND  MAGNETISM. 

50.  Lines  of  force  near  a  bar  magnet. 

51.  Study  of  a  single-fluid  galvanic  cell. 

52.  Study  of  a  two-fluid  galvanic  cell. 

53.  Lines  offeree  about  a  galvanoscope. 

54.  Resistance  of  wires  by  substitution  :  various  lengths. 


VARIOUS  KINDS  OF  SECONDARY  SCHOOLS      333 

55.  Resistance  of  wires  by  substitution  :  cross-section  and 

multiple  arc. 

56.  Resistance  by  Wheatstone's  bridge :  specific  resistance 

of  copper. 

57.  Temperature  coefficient  of  resistance  in  copper. 

58.  Battery  resistance. 

59.  Putting  together  the  parts  of  a  telegraph  key  and  sounder. 

60.  Putting  together  the  parts  of  a  small  motor. 

6 1.  Putting  together  the  parts  of  a  small  dynamo. 

"  Professor  Carhart  suggests  forty  experiments  similar  to  these. 
Twenty-four  of  these  coincide  exactly  in  title  with  items  in  the 
above  list.  The  following  fourteen  are  new,  but  many  of  them 
are  probably  implied  in  the  list  of  sixty-one  : 

The  Jolly  balance. 

Laws  of  the  pendulum. 

Pressure. 

Curve  of  magnetization. 

Action  of  current  on  needle. 

Fall  of  potential  in  conductor. 

E.  M.  F.  of  cell. 

The  tangent  galvanometer. 

Velocity  of  sound  in  solids  (Kundt). 

La\v  of  length  for  strings  (sound). 

Law  of  diameter  for  strings  (sound). 

Law  of  tension  for  strings  (sound). 

Law  of  reflection  (light). 

Measurement  of  angle  of  prism  (light)."1 

The  next  following  quotation  is  an  extract  from  the  Defini- 
tion of  Requirements  issued  by  the  College   En-  .  ti 
trance    Examination   Board  of  the   Middle  States  Middle  states 
and  Maryland,  February  i,   1901. 

1  In  the  NEW  ENGLAND  JOURNAL  OF  EDUCATION  for  December  26, 
1901,  and  January  2  and  9,  1902,  Mr.  Stratton  D.  Brooks,  High  School 
Visitor  for  the  University  of  Illinois,  has,  under  the  title,  "  Suggested 
List  of  Experiments  in  Physics,"  worked  over  this  N.  E.  A.  list  and 
given  corresponding  references  to  several  well-known  text-books. 


334      VARIOUS  KINDS  OF  SECONDARY  SCHOOLS 

"  8  Physics. 

"  The  requirement  in  physics  is  based  on  the  report  of  the 
Committee  on  Physics  of  the  Science  Department  of  the  Na- 
tional Educational  Association. 

"  It  is  recommended  that  the  candidate's  preparation  in 
physics  should  include  : 

"a.  Individual  laboratory  work,  comprising  at  least  thirty- 
five  exercises  selected  from  a  list  of  sixty  or  more,  not  very 
different  from  the  list  given  below. 

"  b.  Instruction  by  lecture-table  demonstrations,  to  be  used 
mainly  as  a  basis  for  questioning  upon  the  general  principles 
involved  in  the  pupil's  laboratory  investigations. 

"  c.  The  study  of  at  least  one  standard  text-book,  supple- 
mented by  the  use  of  many  and  varied  numerical  problems, 
1  to  the  end  that  the  pupil  may  gain  a  comprehensive  and 
connected  view  of  the  most  important  facts  and  laws  in  ele- 
mentary physics.7 " 

The  list  of  titles  of  experiments  which  follows  this  passage  in 
the  original  context  is  precisely  the  same  as  that  numbered  from 
i  to  6 1  in  the  Report  of  the  National  Education  Association 
and  in  the  Harvard  Descriptive  List. 

It  appears,  then,  that  we  have,  in  the  course  of  work  outlined 
by  the  preceding  quotations,  a  type  of  college  entrance  require- 

ment  in  physics  which  is  tolerably  well  defined  and 
of  Such  a  widely  approved.  Whether  this  type  is  established 

and  maintained  as  generally  as  it  is  approved,  may 
be  an  open  question.  In  that  part  of  the  country  which  comes 
under  my  personal  observation,  it  is  very  generally  established. 
But  in  this  same  region  the  boys  who  go  through  a  high  school 
course,  without  having  preparation  for  college  in  view,  do  not, 
as  a  rule,  take  just  this  course  of  physics.  They  take  one  which 
is  more  "  practical  "  or  more  "  general  "  or  more  "  popular," 
almost  always,  I  believe,  a  course  that  involves  less  close  atten- 
tion and  hard  thinking.  This  fact  naturally  raises  a  number  of 


VARIOUS  KINDS   OF  SECONDARY  SCHOOLS      335 

questions.  Is  the  college  requirement,  as  interpreted  and 
maintained  by  Harvard,  for  example,  more  severe  than  it  should 
be?  Are  its  applications  to  every-day  life  too  remote?  Does 
it  require  too  much  use  of  mathematics?  Does  it  have  too 
large  a  proportion  of  painstaking  laboratory  work,  and  too  little 
in  the  way  of  lecture-room  exhibitions  ?  In  particular,  should 
the  course  make  great  use  of  the  projecting  lantern,  with  a  large 
collection  of  interesting  "slides,"  illustrating  scientific  objects 
of  general  or  local  importance  ?  Do  the  teachers  who  devise 
the  courses  of  physics  study  followed  in  "  English  high  schools," 
and  other  schools  of  the  same  general  character,  virtually  express 
an  unfavourable  judgment  of  the  college  requirement  physics 
for  boys  who  are  not  to  go  to  college? 

It  is  possible  that  some  of  these  questions  would  be  and 
should  be  generally  answered  in  the  affirmative,  but  this  is  not 

the  inevitable  conclusion.     There  is  still  the  possi-  T 

Essential 

bility  that  those  who  have  advocated l  the  same  Difference  in 
work  for  boys  who  are  to  go  to  college  as  for  boys 
who  are  not  to  go  to  college  have  overlooked  one  very  impor- 
tant fact,  namely,  that  the  two  sets  of  boys  may  not  be  just  alike 
in  their  mental  traits  and  attainments.  As  a  rule,  so  far  as  my 
observation  and  inquiry  have  gone,  they  are  notably  different, 
the  boys  who  naturally  go  to  an  "  English  high  school "  being 
less  scholarly  and  more  narrowly  utilitarian  in  their  views  than 
their  contemporaries  and  associates  who  naturally  go  to  a 
"  Latin  school." 

Moreover,  I  can  see  little  prospect  of  the  disappearance  or 
even  the  diminution  of  this  unlikeness.  The  now  well  estab- 
lished practice  of  teaching,  in  the  English  high  schools,  such 
arts  as  book-keeping,  short-hand,  and  typewriting,  inevitably 
draws  into  these  schools  a  numerous  class  of  boys  and  girls  who 
by  birth  and  home  influence  have  received  little  of  scholarly 
capacity  or  impulse.  Yet  their  parents  demand,  and  with  good 
show  of  reason,  that  if  public  money  is  spent  to  advance  the  few 

1  See  the  Report  of  the  Committee  of  Ten,  which  is  very  emphatic  on 
this  point. 


336      VARIOUS  KINDS  OF  SECONDARY  SCHOOLS 

to  the  doors  of  college,  with  the  comparatively  profitable  learned 
professions  in  view  beyond,  public  money  shall  be  spent  to 
advance  the  many  toward  the  practice  of  their  useful  and 
honourable,  if  less  distinguished,  vocations.  The  ordinary  city 
high  school  will  therefore  continue  to  have  a  general  class  of 
pupils  who  are  not  capable  of  going  side  by  side  with  the  pupils 
of  the  Latin  schools,  —  a  class  who  have  left  the  grammar  schools 
comparatively  old,  and  will  leave  the  high  school  at  a  lower  in- 
tellectual level  than  their  Latin  school  contemporaries,  unless 
the  course  of  the  former  school  is  made  longer  than  that  of 
the  latter,  which  is  not  likely  to  be  the  case. 

Furthermore,  even  if  the  natural  difference  in  kind  of  pupils 
did  not  exist,  the  fact  that  the  pupils  in  one  school  are  pre- 
Stimulusof  Parmg  to  meet  "requirements  set  by  an  authority 
College  Re-  outside  the  school,  while  the  pupils  in  the  other 
school  are  without  this  stimulus,  will  probably 
always  keep  the  general  standard  of  the  work  higher  in  the 
former  school  than  in  the  latter.  It  is  very  doubtful  whether 
local  authority,  or  even  the  authority  of  any  state  board  of 
education,  unsupported  by  the  strongly  asserted  requirements 
of  colleges,  can  ever  be  depended  on  to  keep  the  general 
standard  of  graduation  from  the  high  school  up  to  the  proper 
level  of  admission  to  college.  A  school  which  sends  but  few 
boys  to  college  will  prepare  but  few  boys  for  college. 

What,  then,  should  such  a  school  undertake  to  do  in  physics  ? 
Should  it  follow  the  college  preparatory  course  as  far  as  it  can, 
What  Hi  h  ta^mg  na^  or  two-thirds  of  it,  for  example;  or 
Schools  should  it  maintain  a  course  designed  with  especial 

reference  to  the  character  and  aims  of  its  own 
pupils  ?  I  cannot  doubt  that  the  latter  alternative  will  prevail, 
and  ought  to  prevail,  though  it  should  be  the  constant  effort  of 
all  school  authorities  to  broaden  and  elevate,  so  far  as  this  may 
be  practicable,  the  ideas  of  their  pupils  as  to  what  is  attainable 
and  what  is  worth  while. 

Without  directly  following  the  college  requirement  course  in 
physics,  the  high  school  course  has  been  profoundly  influenced 


VARIOUS  KINDS   OF  SECONDARY  SCHOOLS     337 

by  it,  and  will  doubtless  continue  to  be  so.  On  the  other 
hand,  it  behooves  those  of  us  who  have  most  to  do  with  the 
college  requirement,  to  keep  watch  of  the  development  of 
physics  in  the  high  schools,  with  the  hope  of  finding  therein 
examples  which  we  may  profitably  follow. 

For  the  high  school  course  in  physics,  as  distinguished  from 
the  college  requirement  course,  there  is  not,  so  far  as  I  am 
aware,  any  general  description  arrived  at  by  formal   ph  sicsin 
consensus  of  opinion.     The  following  extract  from   Brookiine 
the  official  description  of  the  physics  work  in  the 
high  school  of  Brookiine,   Massachusetts,  gives  account  of  a 
course    developed    by  Mr.   John    C.   Packard,  the  teacher  of 
physics   in  that  school,  which   is   in  marked    and   interesting 
contrast  with  the  college  requirement  course  : 

"  There  are  two  courses  in  physics. 

"  i.  The  so-called  Popular  Course,  the  fundamental  aim  of 
which  is  : 

"  (a)  To  develop  in  the  pupil  the  habit  of  steady,  persistent, 
logical  thinking  ; 

"  (b)  To  render  him  fairly  intelligent  in  reference  to  his  own 
scientific  environment ; 

"  (c)  To  beget  a  sense  of  power  in  his  own  ability  to  appre- 
ciate scientific  truth  and  to  draw  legitimate  conclusions  from 
simple  data ; 

"  (d)  To  teach  him  to  apply  the  elements  of  Algebra  and 
Geometry  to  the  problems  of  daily  life,  and  finally 

"  (e)  To  arouse  within  him  a  deep  sense  of  appreciation  of 
all  that  modern  science  has  done  and  is  still  doing  for  the  com- 
fort and  convenience  of  the  race. 

"With  these  ends  in  view  the  head  of  the  department  in 
common  with  many  others  has  discovered  that  but  very  little 
reliance  can  be  placed  upon  the  ordinary  text-book,  since  so 
few  opportunities  are  given  in  the  average  manual  for  any 
original  independent  thinking  and  since  in  general  such  books 
contain  so  little  of  anything  like  a  practical  application  of  the 
principles  of  physics  to  the  phenomena  of  daily  life.  He  has  felt 


338      VARIOUS  KINDS  OF  SECONDARY  SCHOOLS 

obliged  therefore  to  substitute  for  such  text-books,  as  others 
have,  a  special  manual,  as  yet  in  manuscript  form,  in  which  the 
student  is  told  as  little  as  possible  directly,  but  is  given,  practi- 
cally, a  series  of  original  exercises  in  Mechanics,  Optics,  and 
Electricity  which  he  is  to  work  out  by  the  aid  of  a  set  of  simple 
apparatus,  his  mathematical  instincts,  and  his  own  brain,  and 
apply  in  a  continuous  sequence  suggested  by  an  abundance  of 
questions,  problems  and  references  to  the  affairs  of  daily  life. 

"The  aim  is  to  be  thoroughly  practical.  In  Hydraulics,  for 
instance,  more  attention  is  paid  to  the  water-meter,  the  simple 
motor,  and  the  turbine  than  to  the  lifting  pump,  the  ram  and 
the  breast-wheel,  as  the  average  man  is  more  likely  to  see  and 
use  the  former  than  the  latter  series.  In  Optics  again,  the 
camera,  the  opera  glass,  and  the  spyglass  are  dealt  with  more 
fully  than  the  telescope  and  the  compound  microscope  for  the 
same  reason. 

"  Continual  reference  is  made  to  the  current  literature  of  the 
day  and  to  the  science  of  Boston  and  vicinity. 

"  It  is  intended  that  a  series  of  illustrated  lectures  shall 
accompany  the  course  giving  a  brief  summary  of  the  history 
of  Physics  and  a  glimpse  of  the  wonderful  scientific  achieve- 
ments of  our  own  age. 

"  The  work  is  distributed  somewhat  as  follows  :  — 

"  September,  October,  November,  —  Mechanics,  including 
Hydrostatics  and  Pneumatics. 

11  December,  January,  February,  —  Optics. 

"  March,  April,  May,  —  Electricity. 

"  June,  —  Review. 

"  Toward  the  close  of  the  school  year  special  topics  are 
suggested  for  more  exhaustive  treatment  than  is  possible  in 
the  regular  classroom  work.  Each  pupil  is  expected  to  choose 
one  or  more  of  such  topics  and  to  present  an  illustrated  paper 
upon  the  subject  selected,  at  the  end  of  the  year. 

"Among  the  topics  recently  suggested  may  be  mentioned 
the  following :  — 

i.    Mechanics  of  the  Clock. 


VARIOUS  KINDS  OF  SECONDARY  SCHOOLS     339 

2.  Mechanics  of  the  Bicycle. 

3.  Mechanics  of  the  Sewing  Machine. 

4.  Hughes'  Induction  Balance. 

5.  The  Microphone. 

6.  Consumption   of    Gas,    Water   and    Electricity  in  the 
Household. 

7.  Testing  a  Water-Meter. 

8.  The  Fire-alarm  System  of  Brookline. 

9.  School-room  Ventilation. 

10.  The  Long-Distance  Telephone. 

1 1 .  The  Transformer. 

12.  The  Gas-Engine. 

13.  The  Horse  Power  of  an  Electric  Motor. 

"  This  entire  course,  extending  over  one  year's  time,  is  re- 
quired of  the  sub-classical,  the  scientific  and  the  manual  train- 
ing pupils  and  at  least  one-half  the  course,  i.  e.,  the  first  five 
months,  of  the  classical. 

"  The  time  is  equally  divided  between  laboratory  and  lecture- 
room  work,  each  requiring  two  periods  per  week  beside  the 
usual  preparation  for  a  full  study. 

"  Complete  notes  are  kept  by  the  pupils,  of  both  the  labora- 
tory and  the  lecture  work.  These  notes  are  inspected  from 
time  to  time  by  the  instructor,"  etc. 

I  am  far  from  asserting  that  the  course  outlined  by  Mr.  Pack- 
ard is  not  better  for  the  average  high  school  pupil,  boy  or  girl, 

than  the  college  preparatory  course,  which  also  is 

*  Problem  to  be 

given  in  the  same  school.    Mr.  Packard  and  others   Solved  by 

who,  like  him,  have  worked  out  the  problem  of  gen-  ExPenence- 
eral  high  school  physics  approximately  to  their  own  satisfaction 
on  somewhat  new  lines,  will  do  a  service  to  the  public  by  put- 
ting the  results  of  their  experimentation  into  the  form  of  text- 
books or  manuals  available  for  all  teachers.  These  books  may 
or  may  not  prove  to  be  generally  acceptable  and  usable ;  but 
in  any  case  they  will  be  an  important  contribution  to  that  vigor- 
ous trying-out  process  through  which  all  methods  of  science 
teaching  are  now  going  in  the  schools  of  this  country. 


340      VARIOUS  KINDS  OF  SECONDARY  SCHOOLS  ' 

The  word  of  caution  which  I  would  give  to  those  who  aim 
especially  to  make  their  teaching  "practical"  is,  that  they 
should  beware  of  encouraging  the  idea,  which  many  of  their 
pupils  are  only  too  much  inclined  to  hold,  that  the  object  of 
schooling  is  to  give  a  certain  final  and  sufficient  store  of  knowl- 
edge and  not,  rather,  so  to  fit  the  pupil  that  he  may,  after  his 
school  days  are  over,  go  on  increasing  in  knowledge,  finding 
constantly  new  uses  for  that  stock  of  elementary  fundamental 
ideas  which  a  well  devised  school  course  should  inculcate.  To 
this  suggestion  the  teacher  will  perhaps  reply  that  the  average 
high  school  pupil  has  not  sufficient  initiative  and  imagination  to 
find  for  himself  the  use  of  abstract  ideas,  and  that  the  attempt  to 
implant  such  ideas  in  a  mind  essentially  concrete  is  labour  and 
opportunity  lost.  I  have  no  confident  answer  to  make  to  such 
an  assertion.  The  problem  here  is  to  find  the  right  proportion 
of  those  constituents  which  all  admit  to  be  necessary.  There 
is  no  hard  and  fast  rule  to  be  laid  down. 


CHAPTER  XI 

ON   THE   PRESENTATION   OF   DYNAMICS 

REFERENCES. 

Magnus,  P.  Lessons  in  Elementary  Mechanics.  London  and  New 
York,  Longmans,  Green  &  Co.  1892.  Pp.  377. 

Maxwell,  J.  C.  Theory  of  Heat.  London  and  New  York,  Long- 
mans, Green  &  Co.  Chapter  IV. 

I  HAVE  not  undertaken  to  give  in  this  book  a  pedagogic  treat- 
ment of  the  various  parts  of  elementary  physics ;  but  there  is 
one  part,  namely,  dynamics,  so  fundamental  yet  so  often 
neglected  or  badly  taught,  that  I  propose  to  give  it  especial 
attention  here. 

It  must  be  admitted  once  for  all  that  the  elementary  ideas  in- 
volved in  questions  of  acceleration  are  difficult  for  the  ordinary 
mind  to  grasp.  The  formulas,  at  least  for  cases  of  Difficultyand 
uniform  acceleration,  are  very  simple,  but  the  Importance  of 
primary  conceptions  underlying  these  formulas, 
the  definite  notions  of  force,  momentum,  and  kinetic  energy, 
the  ordinary  student  rarely  masters  and  retains.  Should  we, 
therefore,  give  up  the  attempt  to  teach  this  part  of  physics  in 
school  courses,  or  the  early  courses  in  college,  and  content  our- 
selves with  giving,  in  mechanics,  the  statical  aspect  only? 

I  fear  that  many  teachers  will  answer  this  question  in  the 
affirmative,  but  I  am  not  yet  ready  to  do  so.  We  cannot  afford 
to  avoid  everything  that  is  difficult  for  the  average  boy,  or  practi- 
cally impossible  for  the  dull  boy.  We  must  conduct  our  classes 
with  some  regard  to  the  most  vigorous  minds  among  our  pupils  ; 
and  such  minds  will  find,  in  the  broadening  of  their  vision 
through  the  study  of  dynamics,  perhaps  the  most  profitable  part 


342       ON  THE  PRESENTATION  OF  DYNAMICS 

of  all  their  training  in  physics.  How  can  we  be  content  to  let 
a  boy  of  eighteen  years  or  older  leave  our  classrooms  without 
having  had  an  opportunity  to  learn  the  meaning  of  the  term 
energy,  as  strictly  used,  —  a  conception  without  which  all  en- 
deavour to  understand  and  use  the  law  of  conservation  of  energy, 
the  grandest,  yet  one  of  the  simplest,  of  the  generalizations  of 
physical  science,  is  feeble,  if  not  futile  ? 

But  may  not  a  man  be  useful  and  happy  who  does  not  under- 
stand the  conservation  of  energy?  Yes,  if  he  knows  that  he 
does  not  understand  it,  and  does  not  profess  to  understand  it. 
But  this  law  is  peculiarly  one  which  many  people  talk  about,  and 
fancy  themselves  to  understand,  while  their  whole  notion  of  it  is 
so  vague  that  it  is  quite  as  likely  to  lead  them  wrong  as  right 
when  they  would  make  any  application  of  it.  The  law  lies  all 
about  us,  and  nearly  every  one  has  some  not  altogether  false 
idea  of  its  meaning,  some  fairly  good  illustration  of  it  at  com- 
mand ;  but  understand  it  he  certainly  does  not,  if  he  has  not 
mastered  the  meaning  of  certain  little  words,  and  certain  short 
formulas,  the  full  significance  of  which  is  not  made  plain  by  the 
experience  and  conversation  of  every-day  life.  Great  thinkers 
groped  long  for  the  full  meaning  of  the  law,  discoursing  mean- 
while of  the  "  conservation  of  force,"  and  using  "  force  "  some- 
times in  its  proper  sense,  sometimes  in  the  sense  of  "  energy," 
feeling  their  own  confusion  of  ideas,  but  unable  to  see  just  where 
their  trouble  lay. 

I  began  this  chapter  by  admitting  the  difficult  nature  of  the 
ideas  used  in  dynamics.  I  believe,  however,  that  the  effort  of 
Difficulty  In-  masteruig  these  ideas  will  be  less  for  the  next  gen- 
creased  t>y  eration  than  for  the  present,  not  through  any  con- 
TeacMni:.  sjderabie  growth  in  the  power  of  the  human  brain 
within  a  few  decades,  but  because  good  methods  of  instruction, 
if  we  can  establish  and  maintain  them,  will  gradually  produce 
teachers  thoroughly  competent  to  guide  their  pupils  through  the 
initial  difficulties  of  dynamics.  That  all  teachers  of  physics  are 
not  yet  in  this  condition,  a  very  brief  tour  of  visits  to  classrooms 
will  show. 


ON  THE  PRESENTATION  OF  DYNAMICS      343 

Not  long  ago,  in  a  flourishing  city  school,  I  heard  part  of  a 
recitation  on  the  meaning  and  application  of  the  law  of  acceler- 
ation, f= ,  where  v  is  the  velocity  imparted  instances. 

in  t  seconds  by  the  force  f  to  the  mass  ni.  The  teacher  re- 
marked to  me  when  I  entered  the  room  that  he  found  it  hard 
to  get  his  pupils  to  understand  the  dyne.  I  expressed  sym- 
pathy j  but,  in  the  discussion  with  pupils  which  presently  fol- 
lowed, the  teacher  repeatedly  gave  his  approval  to  the  following 
statement :  A  dyne  is  the  force  which  will  move  one  gram  one 
centimeter  in  one  second. 

In  another  school,  —  an  excellent  school,  —  I  heard  a  teacher, 
after  giving  his  pupils  to  understand  that  sliding  friction  is  some- 
what less  with  high  velocity  than  with  low  velocity,  —  a  very  doubt- 
ful proposition  in  itself,  —  explain  this  alleged  fact  by  declaring 
that  the  momentum  of  the  moving  body  helps  to  carry  it  over 
the  frictional  obstacles.  The  experiments  under  discussion  were 
such  as  involved  uniform  velocity  of  the  sliding  body. 

In  still  another  excellent  school  I  heard  a  teacher  discuss  the 
pressure  in  a  siphon,  in  operation,  as  if  the  question  were  one  of 
simple  hydrostatics,  assuming  the  pressure  at  a  given  level,  in 
the  stream  within  the  siphon,  to  be  just  as  great  as  the  pressure 
in  the  still  water  at  the  same  level  outside  the  siphon,  thus 
neglecting  altogether  the  difference  of  pressure  used  in  giving 
momentum  to  the  water  entering  the  tube.1 

The  law  that  action  is  equal  to  reaction  and  opposite  in 
direction,  is  so  very  simple  in  form  and  so  easily  remembered 
verbally,  that  probably  most  people  who  have  ever  heard  it 

1  The  case  of  pressure  in  the  siphon,  during  flow,  seems  rather  too 
difficult  for  profitable  discussion,  in  detail,  with  a  school  class  or  a  young 
class  in  college.  I  think  it  better  to  keep  to  the  static  aspect,  consider 
the  siphon  filled,  with  its  lower  end  closed  for  the  moment,  and  merely 
show  that  the  pressure  within  the  siphon  at  this  end  at  this  moment  is 
greater  than  the  atmospheric  pressure,  so  that  water  must  flow  out  as 
soon  as  the  tube  is  opened.  Yet  some  clear  elementary  conception  of 
the  dynamics  of  the  flowing  water  is  needed,  in  order  to  enable  the 
teacher  of  young  pupils  to  see  why  he  had  better  leave  that  matter  un- 
touched by  his  class. 


344      ON  THE  PRESENTATION  OF  DYNAMICS 

think  they  understand  it.  Yet  there  is  plenty  of  evidence  that 
teachers  sometimes  fail  to  realize  and  apply  it,  even  in  simple 
cases  of  collision  of  bodies.  There  is  a  certain  experiment  or 
set  of  experiments,  to  the  devising  of  which  I  have  given  a 
great  deal  of  care  and  thought,  intended  to  illustrate  the  fact 
that  the  algebraic  sum  of  the  momenta  of  two  bodies  is  the 
same  after  their  collision  as  before,  and  that  this  rule  holds 
true  as  well  for  ivory  balls  with  putty  interposed  as  for  ivory 
balls  in  naked  shock.  Yet  once  a  teacher  of  considerable  ex- 
perience, who  now  holds  and  deserves  an  important  position 
in  the  school  system  of  a  large  city,  complained  to  me  that  tins 
set  of  experiments  was  a  comparative  failure,  because,  according 
to  his  observations,  it  seemed  to  indicate  that  inelastic  bodies 
preserved  their  total  momentum  as  well  as  elastic  bodies.  I 
explained  the  situation  to  him  in  a  word ;  he  thanked  me  heart- 
ily, and  has,  I  feel  sure,  ever  since  found  that  particular  experi- 
ment easier  to  deal  with  and  more  profitable  to  discuss  than  it 
used  to  be. 

I  found,  too,  that  another  teacher,  a  well-known  man,  observ- 
ing that  the  total  momentum  after  collision  was  usually,  by  the 
somewhat  defective  method  of  estimation  prescribed  in  the 
experiment  referred  to,  made  to  appear  slightly  less  than  the 
total  momentum  before  collision,  was  in  the  habit  of  teaching 
his  pupils  that  the  difference  found  was  due  to  the  loss  of 
momentum  (or  energy  ?)  in  the  production  of  heat  at  the  colli- 
sion. Of  course,  a  teacher  in  such  confusion  of  mind,  as  to 
the  relations  of  momentum  and  energy,  would  make  a  muddle 
in  the  minds  of  his  pupils. 

x —  Lest  these  instances  of  faulty  teaching  should  be  considered 
\  invidious,  let  me  say  that  I  have  long  since  come  to  the  con- 
I  elusion  that  it  is  unfair  and  unsafe  to  condemn  any  teacher  for 
I  any  single  mistake,  however  glaring. 

It  is  plain  that  a  considerable  part  of  our  trouble  with  ele- 
mentary dynamical  notions  comes  from  our  unfortunate,  but  at 
present  unavoidable,  multiplicity  of  force-units.  We  have,  at  the 


ON  THE  PRESENTATION  OF  DYNAMICS      345 

least,  the  pound  and  the  gram  as  gravitation  units  of  force,  the 
same  names  being  used  also  for  units  of  mass,  and  the  poundal 
and  the  dyne  as  absolute,  or  acceleration,  units  of  Multiplicity 
force.     Some  generations  hence  the  pound  and  the   of  Force- 
poundal  may  have  disappeared  from  common  use,     m  Sf 
the  decimal  system  of  weights  and  measures  being  then  fully 
established ;    but  it   is    doubtful  whether   the    change  will  be 
rapid,  and  in  any  case  we  of  the  present  day  must  face  the 
difficulties  of  the  transition  state.     Perfectly  clear  fundamental 
ideas  on  the  part  of  the  teacher  are  essential  to  success  in  this 
field  of  operations. 

Moreover,  the  teacher  should  have  a  well  thought  out  plan 
of  campaign,  though  he  should  be  able  and  willing  to  change 
this  plan  as  occasion  seems  to  require.  It  is  a  Need  of 
great  mistake  to  insist  that  the  pupil  must  get  his  Simplicity. 
ideas  in  the  same  order  in  which  a  master  of  the  subject  may 
choose  to  arrange  his  own  matured  conceptions.  Such  a 
master  is  apt  to  be  too  subtle  and  guarded  in  his  preliminary 
statements,  to  look  so  far  ahead  as  to  raise  difficulties  which 
have  not  yet  occurred  to  the  pupil,  —  difficulties  the  too  early 
consideration  of  which  confuses  and  discourages  the  beginner. 
It  is  well  to  begin  with  simple  and  rather  dogmatic  statements, 
to  be  supported  by  experiment  and  argument  and  illustration 
as  these  are  consciously  or  unconsciously  demanded  by  the 
class.  Simple  problems,  too,  should  be  given  in  abundance,  in 
order  that  the  pupil  may  acquire  that  firm  grasp  of  ideas  which 
comes  only  by  use. 

To  give  a  pedagogical  syllabus  of  elementary  ideas  and  rela- 
tions in  dynamics  would  be  foreign  to  the  purpose  of  this  book ; 
but  the  tabulation  of  a  few -important  equations  for  Tabulation 
each  of  several  systems  of  units  may  serve  a  useful  of  Equations. 
purpose,  by  showing  similarities  and  differences,  and  even  by 
exhibiting  the  complexity  of  the  present  situation  in  every-day 
dynamics.  In  the  equations  which  are  given  below,  acceleration, 
whenever  mentioned,  is  assumed  to  be  uniform  acceleration, 
and  force,  whenever  mentioned,  is  assumed  to  be  uniform  force. 


34^       ON   THE  PRESENTATION  OF  DYNAMICS 

Moreover,  the  velocity,  v,  is  supposed  to  be  o  at  the  beginning 
of  the  time,  /. 

Equations  for  Acceleration,  Distance  Travelled,  Velocity  Ac- 
quired, Force,  Work,  and  Kinetic  Energy,  with  the  Absolute 
C.  G.  S.  System  of  Units, 

the  dyne  being  the  unit  of  force  and  the  erg  being  the  unit 
of  work  and  of  energy. 

v 

1 i )  a  =  acceleration  —  -,  or  v  =  a  /. 

(2)  d—  distance  travelled  =  -  X  /  =  -  a  /2. 

2  2 

(3)  v~  —  2  a  dt  from  (i)  and  (2). 

(4)  f=—  —  =  m  a,  where  v  is  the  velocity  given  to  the  mass 

m  by  the  force  f  in  the  time  t. 

(5)  w  —  work  =fd. 

When  w  is  entirely  spent  in  giving  kinetic  energy 
to  m,  we  have 

m  v 
X 

2  2 


(6)   k.  e.  =  kinetic  energy  —  w  =fd  —  — -  X  -  /  =  —  mv*. 


Corresponding  Equations  with  the  Gravitation  C.  G.  S. 
System  of  Units, 

the  gram-force,  a  force  equal  to  the  pull  of  gravitation  on  a 
gram  mass,  being  the  unit  of  force  and  the  gram-centimeter 
being  the  unit  of  work  and  of  energy. 

v 

(1)  a  =  acceleration  =  -,  or  v  =  a  t. 

(2)  d  =  distance  travelled  =  -  X  t  —  -  a  /2. 

(3)  z/2  —  2  a  d,  from  (i)  and  (2). 

(4)  /—  —  =  —  a,  where  v  is  the  velocity  given  to  the  mass 

g*       g 

m  by  the  force/" in  the  time  /. 


ON   THE  PRESENTATION  OF  DYNAMICS      347 

(5)  w  —  work  —fd. 

When  w  is  entirely  spent  in  giving  kinetic  energy 
to  /»,  we  have 

m  v      v         mvz 

(6)  k.  e.  =  kinetic  energy  =  w  =fa*= X  -  /  = . 

gt       2         2g 

With  the  Absolute  Foot-Pound-Second  System, 

in  which  the  poundal  is  the  unit  of  force  and  the  foot-poundal 
is  the  unit  of  work  and  of  energy,  we  have  precisely  the  same 
equations  as  with  the  absolute  C.  G.  S.  system. 

With  the  Gravitation  Foot-Pound-Second  System, 

in  which  the  pound-force,  a  force  equal  to  the  pull  of  gravita- 
tion on  a  pound  mass,  is  the  unit  force  and  the  foot-pound  is 
the  unit  of  work  and  of  energy,  we  have  precisely  the  same 
equations  as  with  the  gravitation  C.  G.  S.  system. 

Many  engineers,  in  this  country  at  least,  keep  to  the  gravi- 
tation English  unit  of  force,  and  yet  write 

force  —  mass  X  acceleration.  Mass  in  the 

Language  of 

This  is  as  if  we    should  write  equation   (4)   of  a  Ens*neerine- 

gravitation  system  in  the  form  /=  —  «,  and  call  ~  the   mass. 

S  S 

That  is,  the  engineer  calls  the  mass  of  10  pounds  of  iron 
io^£-.  It  is  to  be  hoped  that  in  time  there  will  be  agree- 
ment between  physicists  and  engineers  as  to  the  meaning  of 
so  important  a  term  as  mass. 


CHAPTER  XII 

PLAN   AND   EQUIPMENT   OF   A  LABORATORY 

LET  us  suppose  the  school,  for  which  we  are  to  provide  a 
laboratory,  to  be  one  of  considerable  size. 

We  have  elsewhere,  see  Chapter  VII.,  seen  reason  to  believe 
that,  for  the  best  results,  the  laboratory  sections  should  number 
not  more  than  fifteen,  though  we  may  well  make  provision  for 
slightly  larger  sections  in  view  of  emergencies. 

We  will  consider  first  the  laboratory  tables.  Very  short 
tables  are  comparatively  expensive ;  very  long  ones  are  too 
Working  much  in  the  way  when  one  has  to  go  around  them. 
Tables.  The  width  should  be  such  as  to  give  plenty  of 

room  for  a  row  of  pupils  on  each  side,  with  somewhat  bulky 
apparatus  before  them,  and  without  the  necessity  of  crowding 
Bunsen  burners  and  steam-boilers,  for  example,  into  close 
proximity  with  other  articles  which  might  suffer  from  the 
association.  A  good  size  for  the  table  is  TO  feet  by  4  feet, 
the  height  being  3  feet.  Such  a  table  will  give  working  room 
for  six  pupils,  three  on  a  side.  Fig.  18  shows  such  a  table  in 
elevation  and  Fig.  19  shows  it  in  plan.  In  Fig.  18,  gg  is  a  gas- 
pipe  having  six  outlets  downward  for  Bunsen  burner  connec- 
tions, and  four  short  horizontal  branches  (see  also  Fig.  19)  for 
ordinary  illuminating  jets.  In  the  same  figure,  18,  bb  is  a 
wooden  bar,  attached  to  the  end  posts  by  means  of  clamps, 
and  adjustable  at  any  height  above  the  table  between  the  gas- 
pipe  gg  and  the  tops  of  the  posts.  From  this  bar  six  brass 
rods  project  horizontally  (see  Fig.  21),  each  i  foot  long  and 
each  provided  with  a  miniature  vise,  a  thin  saw-cut  i  inch 
deep,  crossed  by  a  pinching  screw.  This  vise  is  not,  perhaps, 
important,  but  the  brass  rods  are  very  convenient  for  making 


PLAN  AND  EQUIPMENT  OF  A  LABORATORY      349 

suspensions,  of  spring-balances,  for -example,  in  careful  weigh- 
ing. The  scale  of  Figs.  18  and  19  is  i  cm.  for  i  foot.  Few, 
if  any,  features  of  this  table  are  original  with  me. 


I 


FIG.  18. 

The  four  small  circles  shown  in  the  table-top  in  Fig.  19 
indicate  holes  bored  through  for  suspension  of  pans  bearing 
weights  in  a  certain  exercise  on  the  bending  of  rods.  The 


o 

0        . 

b    \ 

1      b 

^:\ 

I     1 

~T 

IIMIltffi 

,        *  *. 

/P       *-.* 

FIG.  19. 

line  rr  indicates  the  position  of  a  rod  under  observation,  / 
being  position  of  index.  Two  holes  at  mid-length  of  the  table- 
top  are  not  shown  in  Fig.  19. 


350      PLAN  AND  EQUIPMENT  OF  A  LABORATORY 

The  table  should  be  so  made  as  to  keep  a  reasonably  flat 
top,  as  in  some  exercises  a  level  surface  is  very  desirable,  and 
therefore  it  should  have  as  many  as  six  legs.  Pine  and  ash 
are  good  materials.  Oak  is  objectionable  on  account  of  its 
tendency  to  warp. 

If  the  plan  of  the  course  to  be  given  involves  furnishing  each 
member  of  the  class  with  a  particular  set  of  apparatus,  which 
he  alone  is  to  use  and  for  which  he  must  be  responsible,  it  may 
be  necessary  to  provide  drawers  or  lockers  in  or  under  the 
tables ;  but  such  a  plan  of  work  is,  I  believe,  uncommon,  and 
I  greatly  prefer  plain  tables  with  no  such  receptacles  ;  for  these 
latter  interfere  with  certain  uses  of  the  tables  and,  being  neces- 
sarily without  glass  fronts,  hide  whatever  may  be  within  them. 

Let  us  suppose  that  we  have  three  of  these  tables,  accommo- 
dating, if  need  be,  eighteen  pupils  in  individual  work. 

If  now  we  had  a  very  long  room  lighted  on  one  side,  we 
might  put  all  the  tables  in  line  near  the  windows;  but  this 
The  Labora-  would  not  be  a  very  good  arrangement,  for  it  would 
toiy  Room.  put  one  iine  Of  pUpils  with  their  backs  to  the  light, 
and  the  other  line  with  their  faces  to  the  light,  —  a  disposition 
of  the  class  unfavourable  in  some  exercises  to  those  facing  the 
windows ;  for  sometimes  the  parts  of  the  apparatus  demanding 
their  most  critical  observation  would  be  in  the  shadow  of  other 
parts.  We  will  suppose  the  room  (see  A  in  Fig.  20)  to  be 
oblong,  lighted  on  one  side  and  one  end,  and  will  place  the 
tables,  i,  2,  3,  crosswise  of  this  room,  with  one  end  of  each 
distant  about  3  feet  from  the  lighted  long  side.  A  shelf  sup- 
ported by  brackets  on  the  wall  is  very  useful,  and  we  will  sup- 
pose such,  a  shelf,  15  inches  wide,  to  run  along  the  lighted  end 
of  the  room  at  the  height  of  the  working  tables.  See  7.  Our 
room  should  contain  also  a  large  soapstone  sink,  5a,  with  an 
adjacent  slop-table,  5,  for  holding  battery  materials,  etc.,  a  table 
for  reference  books,  4,  another,  6,  for  demonstration  apparatus, 
a  wall  blackboard,  9,  and  a  long  row  of  cases,  8,  for  storing  ap- 
paratus. Ample  provision  of  space  for  all  these  things,  arranged 
as  in  Fig.  20,  A,  gives  us  a  room  35  feet  long  and  25  feet  wide. 


PLAN  AND  EQUIPMENT  OF  A  LABORATORY      351 

* 

The  apparatus  cases  should  be  about  2  feet  deep,  easy  range 
for  the  adult  arm,  and  the  top  not  more  than  6.5  feet  above 
the  floor.     Much  bulky  apparatus,  of  such  a  nature  Apparatus 
as  not  to  be  easily  injured,  can  well  be  placed  on  Cases»  etc- 
top  of  the  cases.     The  shelves  should  be  adjustable  at  various 
heights,  unless  some  one  knows  the  apparatus  well  enough  to 
place  them  in  advance.     The  highest  shelf  should  not  be  more 
than  5  feet  above  the  floor. 


A  few  drawers,  for  cork-stoppers,  rubber  tubing,  small  hard- 
ware, etc.,  and  a  few  cupboards  for  glassware,  crockery,  record 
books,  and  other  things  more  useful  than  sightly,  can  be  placed 
in,  or  under,  the  tables  for  books  and  demonstration  apparatus. 

Nothing  has  yet  been  said  here  in  regard  to  the  height  of  the 
laboratory  ceiling,  or  the  number  and  dimensions  of  the  win- 
dows. It  goes  without  saying  that  the  room  should  be  well 
lighted.  Fig.  20  indicates  seven  windows,  each  4  feet  wide. 
As  to  the  height  of  the  ceiling,  there  are  few  experiments  which 
demand  greater  height  than  that  of  the  ordinary  room  in  a  mod- 


352      PLAN  AND  EQUIPMENT  OF  A  LABORA  TORY 

ern,  well  constructed,  school  building,  and  it  would  be  hardly 
justifiable  to  make  an  exceptional  height  for  the  sake  of  these 
few  experiments. 

We  must  presently  consider  the  lecture-room  and  the  prepa- 
ration-room, or  workshop.  As  the  latter  is  a  necessary  adjunct 

to  both  the  laboratory  and  the  lecture-room,  it  may 
Workshop.  J 

well  be  placed  between  them,  if  this  arrangement 

is  consistent  with  the  general  plan  of  the  school-building,  of 
which  we  assume  the  rooms  for  physics  to  be  a  part.  A  common 
form  for  such  a  building,  in  the  case  of  public  schools,  is  a  long 
main  body,  with  rather  broad  hall-ways,  or  passageways,  run- 
ning along  its  rear,  and  with  a  wing  at  each  end.  At  the  end 
of  a  passageway  (see  E,  Fig.  20),  and  in  line  with  it,  there  is 
likely  to  be  a  long  narrow  space,  sometimes  utilized  as  a  coat- 
room.  This  space,  which  I  shall  assume  to  be  10  feet  wide, 
will  here  be  taken  as  a  workshop  and  general  utility  room  (B, 
Fig.  20).  Circumstances  must  determine  whether  the  lecture- 
room  or  the  laboratory  shall  occupy  the  rear  of  wing. 

The  plan  shown  in  Fig.  20  does  not  undertake  to  provide 
for  instruction  in  the  use  of  tools,  or  for  the  manufacture  of 
much  apparatus,  but  only  for  such  operations  of  construction 
and  repair  as  the  energetic  teacher  must  be  prepared  to  under- 
take. This  equipment  should  include  a  work-bench  and  a  lathe, 
with  tools  for  working  in  both  metal  and  wood,  an  emery  wheel 
for  sharpening  tools,  and  facilities  for  soldering  and  glass-blow- 
ing. The  last  two  operations  may  use  a  blast  lamp  in  common, 
and  should  therefore  be  carried  on  near  each  other.  The  blast 
of  air  for  the  lamp  can  be  furnished  by  means  of  a  Richards 
pump,  with  compression  chamber,  placed  in  a  sink.  From 
such  a  pump,  with  a  good  head  of  water,  a  sufficient  current  of 
air  for  the  lamp  can  be  carried  many  feet  through  a  half-inch 
pipe.  The  teacher  should  have  also  at  his  service  an  outfit  for 
photographing  and  for  blue-printing,  and  the  dark  room  for 
developing  may  well  be  placed  at  the  inner  end  of  the  work- 
room. Of  course  there  should  be  shelves  and  a  case  of  drawers 
for  stock  and  tools. 


PLAN  AND  EQUIPMENT  OF  A  LABORATORY     353 

All  these  things  being  placed,  and  also  an  .electric  motor  for 
i  power,  which  may  be  on  the  floor  or  on  a  platform  above  the 
i  rest  of  the  machinery,  there  will  remain  in  room  B  a  consider- 
i  able  amount  of  space  available  for  storing  the  lecture-room 
|  apparatus.  The  most  convenient  way  of  getting  such  apparatus 
I  into  the  lecture-room,  C,  is  through  a  door  in  the  middle  of  the 
i  wall  behind  the  lecture- table. 

The  width  of  the  lecture-room,  as  shown  in  Fig.  20,  is  35  feet. 
The  depth  I  leave  undetermined,  as  that  should  depend  on  the 
number  of  pupils  it  will  be  required  to  hold.     The  Lecture- 
common  practice  of  making  the  width  of  a  lecture-  Room' 
room  much  greater  than  its  depth  is  unfortunate.     The  front 
seats  at  the  sides  in  such  a  room  are  undesirable,  for  they  give 
a  very  oblique  and  therefore  indistinct  view  of  things  on  the 
blackboard  which  is  behind  the  lecture-table. 

The  lantern-screen  is  also  supposed  to  be  behind  this  table, 
on  a  roll  which  draws  it  up  out  of  sight  when  it  is  not  needed ; 
but,  if  the  ceiling  is  high,  the  wall  space  above  the  blackboard,  if 
finished  smooth  and  white,  serves  exceedingly  well  as  a  screen 
for  projections.  The  lantern  itself  is  supposed  to  be  at  the 
rear  of  the  room.  The  one  window  shown  in  the  wall  of  C 
is  supposed  to  be  on  a  level  with  the  lecture-table,  so  that 
a  mirror  placed  at  this  window  will  put  the  sun's  rays  at  the 
service  of  the  lecturer,  provided  this  window  has  a  southerly 
outlook. 

At  the  lecture-table  sink  it  is  well  to  have  two  faucets,  one  of 
which  should  end  in  a  screw,  so  as  to  admit  of  ready  connec- 
tion  with  an  aspirator.     It  is  well  to  provide  the  Some 
table  with  a  horizontal  adjustable  bar  carried  by  Equipments, 
end  posts,  like  the  bar  and  posts  of  the  working-tables  (see 
Figs.  18  and  19)  ;  but  as  these  objects  might  sometimes  obstruct 
the  view  of  something  on  exhibition  beyond  them,  the  posts 
should  be  so  attached  to  the  table  as  to  be  easily  removed  or 
replaced. 

For  a  source  of  low  voltage  electricity,  which  one  needs  to 
use  occasionally  at  the  lecture-table,  the  arrangement  illustrated 

23 


354      PLAN  AND  EQUIPMENT  OF  A  LABORATORY 

by  the  following  diagram  (Fig.  21)  is  to  be  recommended: 
Si  and  S2  are  two  storage  cells  of  the  ordinary  type,  connected 
with  each  other  in  series  through  the  binding-posts  b2  and 
b8.  These  cells  are  charged  by  a  battery,  DD,  of  six  large 
gravity  Daniell  cells  connected  with  each  other  in  series.  The 
connections  here  shown  are  maintained  all  the  time,  so  that  the 
storage  cells  are  always  ready  for  use.  If  two  volts  are  needed 
for  use  in  any  experiment,  connection  is  made  with  the  binding- 
posts  bi  and  b2,  or  with  b3  and  b4.  If  four  volts  are  needed, 
connection  is  made  with  bL  and  b4.  All  the  cells  should  be 
covered  so  as  to  diminish  evaporation. 


Fig.  21 


A  convenient  and  useful  device  for  controlling  strong  currents 
by  variation  of  resistance  is  in  the  form  of  a  column  of  carbon 
plates,  each  about  four  inches  long  and  \  inch  thick,  held  in  a 
frame  between  two  thick  end  plates  of  brass,  one  of  which  can 
be  pressed  against  the  adjacent  carbon  plate  by  means  of  a 
screw  passing  through  one  end  of  the  frame.  The  greatest 
defect  of  this  device  is  that  one  cannot  tell,  without  some  sup- 
plementary measuring  instrument,  how  great  its  resistance  is  at 
any  given  instant. 

The  reflecting  galvanometer  (see  Figs.  15  and  16,  Chapter 
VIII.),  if  the  lecture-room  is  provided  with  such  an  instrument, 
can  be  placed,  when  in  use,  on  a  shelf  just  below  the  blackboard, 
the  inclined  screen  being  placed  above  the  blackboard,  or  the 
whole  outfit  can  be  put  in  one  corner  of  the  room  in  place  of 
the  triangular  apparatus  case,  22  of  Fig.  20. 

If  the  school  is  one  in  which  the  physics  class  is  small,  the 


PLAN  AND  EQUIPMENT  OF  A  LABORATORY     355 

laboratory  room,  with  little  or  no  change  from  its  plan  as  already 
given,  can  be  used  as  a  lecture-room. 

I  have  said  little  in  this  book  in  regard  to  the  general  body 
of  apparatus  with  which  the  physics  department  of  a  well 
equipped  school  should  be  provided,  and  I  shall 
not  now  undertake  to  treat  of  this  matter  at  length.  pparatus' 
Accompanying  the  Harvard  Descriptive  List  of  laboratory 
exercises  is  a  detailed  list  of  apparatus  for  these  exercises, 
which  is  the  product  of  years  of  experience  and  suggestion  and 
gradual  development.  Much  of  this  apparatus,  which  is  simple 
and  inexpensive,  would  be  useful  in  any  beginner's  course  of 
laboratory  physics,  looking  toward  college  or  not  looking 
toward  college.  Moreover,  several  manufacturers  of  school 
apparatus  keep  the  articles  of  the  Harvard  list  in  stock  and 
know  these  articles  by  the  numbers  they  bear  in  that  list,  a  fact 
which  facilitates  ordering  from  them  if  one  has  the  Harvard 
list  at  hand. 

As  to  the  apparatus  for  lecture-room  purposes,  almost  any 
modern  descriptive  text-book  is  a  fairly  good  guide,  though  of 
course  one  should  compare  various  books  and  various  catalogues 
of  dealers  in  apparatus  before  making  any  large  purchase. 


CHAPTER  XIII 

PHYSICS  TEACHING  IN  OTHER  COUNTRIES 
REFERENCES. 

Board  of  Education  of  the  English  Government.  Special  Reports 
on  Educational  Subjects. 

British  Association  Reports,  in  many  places ;  for  example,  in  1889  and 
1890,  "  Suggestions  for  a  Course  of  Elementary  Instruction  in  Physical 
Science." 

Delalain  Freres,  115  Boulevard  Saint-Germain,  Paris,  official  pro- 
grammes of  primary  and  secondary  instruction  in  France. 

Russell,  J.  E.  German  Higher  Schools.  New  York  and  London, 
Longmans,  Green  &  Co.  1899.  ^P-  4^7- 

Sharpless,  I.  English  Education.  New  York,  Appleton  &  Co. 
London,  E.  Arnold.  1892.  Pp.  193. 

WITHOUT  undertaking  an  examination  of  the  state  of  elemen- 
tary physics  teaching  in  all  European  countries,  we  may  well 
inquire  what  it  is  in  Germany,  England,  and  France ;  for  these 
are  the  countries  to  which,  rightly  or  wrongly,  Americans  are  in 
the  habit  of  looking  for  suggestion  and  instruction. 

Germany  has  a  well  established  system  of  physics  teaching  in 
her  schools  as  well  as  in  her  universities,  and  this  system,  if  it 
is  not  the  cause  of  her  eminence  in  physical  research  and  her 
success  in  commercial  scientific  undertakings,  is  at  least  con- 
temporaneous with  these  achievements.  England  has  for  a 
number  of  years  studied  German  methods  of  secondary  educa- 
tion in  science,  hoping  thus  to  find  and  profit  by  the  secret  ol 
her  dangerous  commercial  activity.  It  is  well,  therefore,  that 
we  should  look  first  at  these  same  methods  as  they  are  found 
in  German  schools  below  the  universities.  The  numerous 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES     357 

quotations  given  below,  from  Russell's  German  Higher  Schools?- 
make  this  task  easy. 

It  should  be  said  in  advance  that  in  both  classes  of  the 
higher  schools,  the  classical  gymnasiums  and  the  ra*/-schools,2 
the  full  course  of  study  is  nine  years,  which,  beginning  with  the 
year  of  the  lower  class,  are  numbered  thus,  sexta,  quinta,  quarta, 
unter-tertia,  ober-tertia,  unter-secunda,  ober-secunda^  unter-prima, 
ober-prima.  Many  pupils,  however,  leave  the  schools  at  the 
end  of  six  years,  there  being  a  well  defined  break  in  the  course 
at  that  point. 

(From  p.  330.)  "  The  chief  aim  of  all  instruction  in  the 
natural  sciences  [  including  physics  ]  is  to  cultivate  the  habit  of 
keen  and  accurate  observation,  to  strengthen  the  pupil's  reason- 
ing powers  and  to  increase  his  ability  of  expressing  clearly  what 
he  sees  and  thinks.  The  acquisition  of  a  fund  of  systematic 
knowledge  or  useful  information  is  a  secondary  consideration." 

After  remarking  (p.  333)  that  "the  science  work  in  the  Real- 
schools  is  taken  more  seriously  than  in  the  Gymnasien,"  the 
author  gives,  "  as  a  type  of  what  is  done  in  Prussia  the  course 
of  study  prescribed  in  the  Konigstadtisches  Realgymnasium  of 
Berlin."  The  physics  of  this  course  is, 

"  Unter-secunda.  [Sixth  year].  Physics,  3  hours  [per  week]. 
First  semester :  Frictional  electricity  and  phenomena  out  of 
[taken  from]  the  domain  of  magnetism  and  galvanic  electricity. 
Acoustics  and  optics.  Second  semester :  Mechanics  of  solid, 
liquid,  and  gaseous  bodies.  General  properties  of  matter. 
Parallelogram  of  forces  and  of  motion.  Laws  of  falling  and 
vertically  projected  bodies.  The  simple  machines.  Text-book, 
Jochmann,  Grundriss  der  Experimental  Physik" 

"  Ober-secunda.  Physics,  3  hours.  First  semester :  Mag- 
netism and  galvanic  electricity.  Second  semester:  Heat, 
repetition  and  extension  of  mechanics,  especially  of  oblique 
projection  and  of  central  motion.  Text-book,  same  as  in 
Unter-secunda . ' ' 


1  Longmans,  1899. 

2  The  Realgymnasien  and  the  Obtrrealschulm. 


358     PHYSICS   TEACHING  IN  OTHER   COUNTRIES 

"  Unter-prima.  Physics,  3  hours.  First  semester :  Wave 
theory,  acoustics  and  optics.  Second  semester :  Mechanics. 
In  both  semesters,  reviews  and  more  thorough  mathematical 
treatment  of  particular  parts  of  the  earlier  work.  Solution  of 
problems.  Text-book,  same  as  in  Unter-secunda.  (Physical 
laboratory  exercises,  2  hours,  optional.)  " 

"  Ober-prima.  Physics,  3  hours.  First  semester :  Optics. 
Second  semester  :  Mechanics.  In  both  semesters,  reviews  and 
more  thorough  discussion  of  parts  of  the  earlier  work,  especially 
quantitative  determinations  and  methods  of  measurement. 
Text-book,  same  as  above.  (Physical  laboratory  exercises,  2 
hours,  optional.)  " 

(From  p.  345.)  "  According  to  the  Prussian  syllabus  of  1892, 
the  course  in  physics  is  divided  into  two  parts.  The  first  part 
is  intended  to  give  the  pupil  some  notion  of  the  fundamental 
principles  of  the  subject  as  exemplified  in  the  ordinary  and 
more  familiar  manifestations  of  nature ;  it  is  concluded 
with  Unter-secunda.  The  continuation  of  the  course  aims  to 
give  those  who  may  pass  on  to  the  university  a  more  compre- 
hensive understanding  of  physical  laws  and  their  applications. 
This  division  is  in  strict  accord  with  a  prevailing  idea  of  the 
Berlin  Conference  [in  which  the  present  Emperor  figured  so 
prominently],  that  those  leaving  school  at  sixteen  should  have 
as  symmetrical  a  training  as  it  is  possible  to  provide.  Only  the 
most  important  principles  are  taught  in  the  first  part  of  the 
course,  and  much  stress  is  put  upon  the  application  of  these  to 
the  practical  affairs  of  every-day  life.1 

"  The  advanced  course  is  first  of  all  a  repetition  and  exten- 
sion of  the  earlier  work,  and  in  the  second  place  a  more 
extended  mathematical  treatment  of  the  subject.  This  latter 
phase  of  the  work  can  be  done  successfully  only  in  the  Real- 
schools,  inasmuch  as  the  mathematics  taught  in  most  Gymna- 
sien  is  insufficient  for  the  purpose." 


1  "  Full  information  of  what  may  be  accomplished  in  this  preliminary 
course  may  be  found  in  the  Zeitschrift  fur  den  physikalischen  und  chem- 
ischen  Unterricht,  JahrgangN,  Heft  4  (April,  1892)." 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES    359 

(From  p.  346.)  "  A  text-book  is  always  employed  in  teach- 
ing physics  and  chemistry,  precisely  in  the  same  manner  as  in 
teaching  natural  history.  But,  unlike  the  methods  commonly 
used  in  American  and  English  schools,  German  teachers  invari- 
ably use  these  books  for  reference  only.  It  is  not  expected, 
however,  that  they  will  take  the  place  of  the  elaborate  compen- 
diums  found  in  each  school-room  ;  they  are  mere  outlines  of  the 
subject,  intended  to  assist  the  pupil  in  making  scientific  classi- 
fications, not  for  purposes  of  recitation.  In  fact,  as  we  have 
repeatedly  observed,  the  German  teacher  never  assigns  a  lesson 
in  advance  to  be  studied  at  home.  Recitations,  therefore,  at 
least  in  the  American  sense,  are  unknown. 

"A  typical  lesson  always  includes  a  review  of  the  principles 
and  experiments  of  past  lessons  which  have  a  direct  bearing 
upon  what  is  next  to  be  presented.  The  teacher  explains  the 
nature  of  the  apparatus  with  which  he  is  to  deal,  and  places  it 
upon  his  desk  in  full  view  of  the  entire  class.  .  .  .  Certain 
conditions  are  stated,  and  the  class  questioned  as  to  what  results 
may  reasonably  be  expected.  This  preliminary  discussion  hav- 
ing carefully  prepared  the  way  for  a  right  understanding  of 
the  experiment,  the  demonstration  by  the  teacher  follows.  The 
students  are  required  to  make  note  of  the  apparatus  used,  the 
principles  involved,  the  conditions  under  which  the  reaction 
occurred  and  the  results  obtained.  By  means  of  a  running  fire 
of  questions,  the  teacher  keeps  himself  informed  in  regard  to 
the  menial  state  of  his  class  ;  for  it  is  his  duty  to  see  not  only 
that  all  understand  the  trend  of  the  experiment,  but  also  that  its 
significance  is  realized. 

"  German  practice  is  always  consistent  in  its  adherence  to  the 
idea  that  good  teaching  never  leaves  the  pupil  in  doubt.  In 
mathematics  he  is  not  assigned  a  problem  to  wrestle  with  by 
himself  alone,"  etc. 

"  Every  principle  worth  demonstrating  is  illustrated  in  class. 
But  the  teacher  does  more  than  demonstrate ;  he  teaches  as 
well.  And  successful  teaching  requires  that  present  impressions 
be  definitely  related  to  past  experiences.  Wrong  relationships, 


360    PHYSICS   TEACHING  IN  OTHER   COUNTRIES 

or  none  at  all,  are  an  inevitable  consequence  of  misapprehension. 
For  this  reason  the  German  teacher  counts  it  his  duty  to  prevent 
his  students  drawing  wrong  inferences.  They  have  not  yet 
arrived  at  the  stage  of  independent  study ;  that  comes  in  the 
university.  In  secondary  schools  no  time  should  be  wasted  in 
beating  about  the  bush.  The  ability  to  make  an  occasional 
lucky  guess  is  in  nowise  identical  with  sustained  logical  thought. 

"  At  the  conclusion  of  a  lesson  topic,  the  pupil  is  directed  to 
consult  his  text-book  and  afterward  write  up  his  notes.  This 
done,  the  teacher  inspects  the  book  at  his  leisure. 

"  Laboratory  exercises,  if  required  at  all,  are  introduced  at 
this  point,  in  order  that  students  may  themselves  duplicate  the 
experiment  performed  by  the  teacher  or  make  other  demonstra- 
tions putting  to  practical  test  the  knowledge  just  acquired.  The 
function  of  laboratory  practice,  as  will  be  seen,  is  to  make  appli- 
cation of  facts  already  learned,  not  at  all  for  the  purpose  of  pre- 
senting new  truths  or  arriving  at  new  deductions.  Inasmuch  as 
laboratory  practice  is  optional,  and  the  exigencies  of  the  time- 
card  usually  place  it  out  of  school  hours,  few  students  enter  for 
it." 

(From  p.  348.)  "  Probably  the  best  adducible  evidence  of 
the  relative  value  of  the  various  studies,  as  popularly  estimated, 
is  the  part  each  plays  in  the  final  examination.  Judged  in  this 
way,  the  sciences  take  a  low  rank.  Physics  may  be  counted  as 
a  fourth  part  of  mathematics  in  the  gymnasial  examination ;  in 
the  J?#z/-schools,  one  problem  is  assigned  in  physics  and  one  in 
chemistry.1  The  worst  of  it  is  that,  '  nothing  short  of  a  miracle,' 
to  quote  a  German  teacher,  '  can  prevent  the  promotion  of  the 
most  deficient  member  of  the  class,  provided  his  attainments  be 
satisfactory  in  other  subjects.' " 

There  is  much  to  be  commended  in  the  physics  instruction 
which  the  German  boy  receives.  It  does  not  attitudinize,  does 


1  A  foot-note  here  gives  problems  set  at  the  final  examination  (Ar- 
biturientenprlifung)  of  a  Realgymnasium.  The  problems  in  physics  are 
simple,  involving  the  use  of  Ohm's  law,  the  tangent  galvanometer  and 
Wheatstone  bridge. 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES     361 

not  call  itself  by  a  name  which  it  cannot  live  up  to ;  it  drives 
straight  and  hard  at  some  of  the  most  important  objects  of 
study,  a  useful  knowledge  of  physics  and  a  useful  habit  of  look- 
ing at  and  thinking  about  those  physical  phenomena  which  are 
presented  to  the  pupil's  view.  I  do  not  feel  disposed  to  criti- 
cise German  school-teaching  as  too  little  "  inductive  "  or  "  heur- 
istic," though  possibly  it  may  be  so.  Its  chief  defect,  and  a 
serious  one,  seems  to  be  that  it  does  not  give  the  pupil  labora- 
tory work  for  his  own  hands,  and  therefore  leaves  him  wanting 
in  that  actual  experience  of  apparatus  which  is  so  important  for 
any  one  who  must  conduct  or  devise  experiments  or  make  any 
objective  use  of  physics.  Transported  to  America,  where  the 
incentives  to  scholarly  effort  on  the  part  of  young  pupils  are  at 
present  much  less  strong,  and  where  teachers  are  less  thoroughly 
equipped,  than  in  Germany,  the  German  school  system  of 
physics  teaching  would  probably  not  work  well. 

When  we  turn  from  Germany  to  England,  and  attempt  to 
realize  the  state  of  science  teaching  in  the  schools  of  the  latter 
country,  the  field  of  view  grows  suddenly  obscure.  For,  as 
compared  with  Germany,  England  can  hardly  be  said  to  have 
a  system  of  education  :  she  has  rather  a  state  of  development, 
and  in  some  respects  a  rapidly  changing  state,  the  changes 
being  as  rapid  in  science  instruction  as  in  any  other. 

The  Special  Reports  on  Educational  Subjects  issued  by  the 
English  Government 1  contain  a  good  deal  of  interesting  matter 
relating  to  instruction  in  science.  In  volume  6  (1900)  Mr. 
Archer  Vassall,  Assistant  Master  at  Harrow,  writes  as  follows : 

"  In  Public  Schools  [the  endowed  schools  like  Rugby, 
Eton  and  Harrow]  the  teaching  of  science  has  only  recently 
begun  to  take  reasonable  shape,  and  ceased  to  be  a  series  of 
fireworks,  or  isolated  physical  phenomena,  presented  in  a 
casual  and  indigestible  manner  to  the  pupil ;  while  there  has 
been  so  little  of  it  in  the  Preparatory  Schools  [preparatory  to 

1  Vols.  1-3  by  the  "  Educational  Department,"  later  volumes  by  the 
"  Board  of  Education." 


362      PHYSICS   TEACHING  IN  OTHER   COUNTRIES 

the  endowed  Public  Schools]  that  its  past  and  present  state  in 
these  institutions  does  not  require  any  long  exposition. 

"Nevertheless,  now  that  the  large  number  of  subjects  in- 
cluded under  the  head  of  Science  are  more  reasonably  taught 
to  elder  boys  and  others,  there  has  arisen  a  fairly  widespread 
feeling,  amongst  both  parents  and  schoolmasters,  that  some 
elementary  information  on  scientific  subjects  should  be  given 
to  boys  whilst  still  at  Preparatory  Schools,  and  that  these  sub- 
jects afford  valuable  material  for  educating  the  minds  of  such 
boys.  To  their  credit  be  it  said,  Board  Schools  and  Girls' 
Schools  have  for  some  time  realized  this  fact,  and  in  many  of 
them  scientific  subjects  find  a  place  in  the  curriculum. 

"  In  .Preparatory  Schools  the  result  of  this  inclination  has 
been  that  several  tentative  efforts  in  scientific  instruction  have 
been  made,  and  are  still  in  progress  at  many  of  them,  though 
nothing  approaching  the  systematic  ' nature  study'  of  the 
young  American  has  as  yet  been  achieved." 

Mr.  Vassall's  opinion,  as  shown  in  this  article,  is  in  favour  of 
physics,  for  preparatory  schools,  rather  than  chemistry,  and 
strongly  for  laboratory  work  combined  with  lectures,  rather 
than  lectures  alone. 

Volume  2  of  the  Reports  contains  (pp.  389-413)  an  article 
on  "  The  Heuristic  Ifethod  of  Teaching  or  The  Art  of  Making 
Children  Discover  Things  for  Themselves,"  by  Professor  Arm- 
strong. The  "  British  Association  Scheme  "  of  science  instruc- 
tion, to  which  he  frequently  refers,  was  the  outcome  of  the  work 
of  a  committee  of  the  association,  which  was  appointed  in  1887 
and  reported  in  each  of  the  three  following  years.  In  1889 
and  1890  the  committee  printed  in  its  reports  Suggestions  for 
a  Course  of  Elementary  Instruction  in  Physical  Science,  by 
Professor  Armstrong,  who  was  a  member  of  the  committee. 
It  is  evident  that  these  reports  have  had  much  influence  in 
England,  and  Professor  Armstrong,  in  the  article  named  above, 
claims  a  very  marked  degree  of  success  for  teaching  inspired 
by  the  methods  and  principles  set  forth  in  "  The  British  Asso- 
ciation Scheme."  He  states  in  this  paper  that  in  1897  this 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES     363 

scheme  "  was  in  operation  in  no  fewer  than  40  of  the  London 
Board  Schools." 

In  general  terms  this  scheme,  as  originally  set  forth,  is  to 
train  the  pupil  from  childhood  to  observe,  think  about,  and 
experiment  on,  common  things,  air  and  common  liquids  and 
earthy  materials,  for  example,  not  with  a  view  to  making  him 
by  and  by  a  specialist  in  chemistry  or  physics,  but  for  the 
purpose  of  forming  certain  important  habits  and  cultivating 
certain  important  powers,  while  giving  a  considerable  amount 
of  directly  useful  information.  It  is  admitted  that  progress 
will  be  slow,  as  it  is  in  all  the  other  important  studies  of  child- 
hood, but  great  things  in  the  way  of  preparation  for  the  inevi- 
table and  unending  conflict  of  nations,  in  commerce,  industry, 
and  war,  are  hoped  for  by  the  advocates  of  this  scheme  of 
instruction,  if  it  is  undertaken  and  persistently  carried  out. 

The  title  of  Professor  Armstrong's  paper  should  be  read  in 
the  light  of  the  following  passage  (p.  407),  by  which  it  appears 
that  the  "  method  of  discovery "  by  individual  pupils  is  not 
rigidly  adhered  to.  "  No  books  will  be  used,  but  the  class  will 
gradually  write  its  own  book  and  so  come  to  understand  how 
books  are  written ;  for  whenever  an  object  has  been  properly 
studied,  the  teacher,  instead  of  dealing  with  the  scholars  in- 
dividually, will  call  them  to  order  as  a  class,  and  by  judicious 
questioning  will  then  elicit  all  that  is  needed  for  the  description 
of  the  work  done.  The  simplest  possible  account  will  be 
written  on  the  blackboard  as  the  questioning  proceeds,  and  at 
the  close  of  the  lesson  a  senior  pupil  will  copy  this  with  a 
typewriter,  and  each  member  of  the  class  will  afterwards  receive 
a  copy,  which  will  at  once  be  pasted  in  a  book,  to  be  kept  for 
reference  and  used  as  a  reader." 

Appendix  A  to  the  paper  of  Professor  Armstrong  gives  the 
"  Course  of  Instruction  in  Elementary  Science  adopted  [in 
1896]  by  the  Incorporated  Association  of  Headmasters"  of 
secondary  schools l  for  pupils  commencing  the  study  of  physics. 

1  According  to  Sharpless,  EnglisJi  Education  (Appleton,  1892),  "  Sec- 
ondary education  [in  England]  is  now  in  the  hands  of  a  number  of 


364      PHYSICS    TEACHING   IN   OTHER   COUNTRIES 

Professor  Armstrong  speaks  of  this  syllabus  as  "  based  on  the 
British  Association  scheme."  It  is  worthy  of  careful  examina- 
tion. The  headings  under  Elementary  Physics  are : 

1.  Measurement  of  Length. 

2.  Measurement  of  Area. 

3.  Measurement  of  Volume. 

4.  Measurement  of  Mass. 

5.  Measurement  of  Density. 

6.  Measurement  of  Thrust  and  of  Pressure,  of  Pull  and  of 
Tension.     Distinction  between  solids,  liquids,  and  gases. 

70    Measurement  of  the  force  which  a  liquid  exerts  upon 
a  body  immersed  in  it. 

8.  Measurement  of  Temperature. 

9.  Measurement  of  Quantity  of  Heat. 

10.  Measurement  of  Vapour  Pressure. 

11.  Measurement  of  Force  in  pounds  or  grams  weight,  and 
their  Graphic  Representation. 

12.  Resolution  of  Forces. 

13.  Equilibrium  of  Three  Forces. 

14.  Equilibrium  of  Four  or  more  Forces. 

15.  Parallel  Forces. 

1 6.  Centre  of  Gravity. 

17.  Principle  of  Moments,  Levers. 

1 8.  Simple  Machines. 

According  to  Professor  Armstrong  (p.  397)  the  Oxford 
and  Cambridge  Local  Examination  Authorities  have  tried  to 
make  examinations  suited  to  the  science  syllabus  of  the  Head- 
masters' Association.  "  Unfortunately,  however,  their  instruction 
in  no  way  whatsoever  imply  or  involve  heuristic  teaching ;  and 
it  is  only  too  clear  that  that  which  is  fundamental  in  the  recom- 
mendations of  the  British  Association  scheme  has  not  been 
understood."  This  was  printed  in  1897-1898  ;  things  may  be 
different  now. 


private  schools  of  all  degrees  of  goodness  and  badness,  of  a  few  non- 
conformist denominational  schools  which  are  usually  good,  and  of  the 
endowed  schools  for  boys"  (Public  Schools  and  Grammar  Schools). 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES 

The  general  tendency  of  Professor  Armstrong's  writing  seems 
to  be  to  discourage  the  use  of  printed  books  and  to  make  the 
pupil  distrust  accounts  of  what  has  not  been  seen  by  himself  or 
his  classmates.  American  teachers  should,  I  think,  be  slow  to 
follow  this  suggestion.  The  ordinary  American  boy  is  only  too 
willing  to  act  on  the  hint  not  to  study  books  on  physics.  He 
will  do  laboratory  work  cheerfully  enough,  even  when  he  has 
only  the  dimmest  idea  what  it  is  all  about,  but  he  shrinks  from 
the,  to  him,  painful  effort  of  getting  from  a  book  the  definitions 
and  the  reasoning  necessary  to  make  the  laboratory  work  intel- 
ligible. This  is  not  because  he  has  any  predilection  for  the 
"  heuristic  "  method ;  for  he  delights  to  be  told  things  by  word 
of  mouth  instead  of  seeking  them  out  for  himself,  and,  if  not 
persistently  discouraged  from  the  practice,  will  habitually  stand 
with  an  open  book  before  him  and  ask  for  information  that  is 
plainly  given  on  the  printed  pages  beneath  his  eyes.  Nor  does 
the  disinclination  to  reading  necessarily  disappear  with  youth. 
It  often  persists  into  manhood  and  renders  fruitless  the  labour 
of  years. 

Is  it  not  quite  possible  that  the  scientific  pre-eminence  of  the 
Germans  as  a  race  is  due  largely  to  their  habit  of  reading  widely 
and  thoroughly,  of  mastering  by  reading  not  only  the  bulky 
treatises  and  periodicals  of  their  own  language,  but  also  the 
scientific  publications  of  foreign  tongues?  Consider  the  signif- 
icance and  influence  of  such  a  journal  as  the  BEIBLATTER  to  the 
ANNALEN  DER  PHYSIK.  What  testimony  it  gives  to  the  zeal 
of  the  Germans  in  the  study  of  science  through  the  printed 
page. 

The  completeness  with  which  the  educational  system  of 
France  has  been  worked  out  by  a  thoughtful  and  ingenious 
people  makes  it  worthy  of  study.  The  official  programmes  of 
primary  and  secondary  instruction,  with  which  we  are  concerned, 
are  set  forth  in  considerable  detail  in  frequent  publications 
issued  by  Delalain  Freres,  115  Boulevard  Saint-Germain,  Paris. 
Any  one  can  by  reading  these  programmes  get  a  fair  idea  of 


366      PHYSICS   TEACHING  IN  OTHER   COUNTRIES 

what  is  being  done  in  schools  of  any  given  class  throughout 
France. 

In  examining  with  considerable  care  the  parts  relating  to 
physics  in  the  official  programmes  of  the  various  kinds  of  schools, 
I  have  found  nothing  anywhere  which  seems  to  require  or  to 
provide  for  experimental  work  to  be  done  by  pupils,  though  I 
am  informed  that  laboratories  for  pupils  in  physics  do  exist  in 
some  lycees.  Indeed,  for  students  taking  the  classical  course 
I  find  ^nothing  under  chemistry,  even,  which  seems  to  make 
provision  for  laboratory  work  by  pupils  until  the  Classe  de 
Mathcmatiques  Specials,  for  young  men  who  have  completed 
the  ordinary  lycee  course,  is  reached.  Here  twelve  chemical 
"  manipulations,"  each,  apparently,  occupying  the  student  four 
hours,  are  strictly  prescribed.1  In  the  "  modern  "  course  of  the 
lycees  there  is  some  little  provision  for  laboratory  work  in 
chemistry  in  the  third  class,  the  second  class,  and  the  first  class 
(sciences],  about  eighty  hours  in  all. 

In  the  elementary  primary  schools  there  are  object  lessons 
(lemons  de  chases).  Although  the  object  of  the  primary  school 
instruction  is  frankly  and  emphatically  utilitarian,  an  attempt  is 
made  to  cultivate  the  philosophical  imagination  of  the  pupils. 
"  In  all  instruction,  the  master,  at  the  beginning,  makes  use  of 
tangible  objects,  has  the  children  see  and  touch  the  things,  puts 
them  in  the  presence  of  concrete  realities ;  afterward,  little  by 
little,  he  exercises  them  in  getting  at  the  abstract  idea  from  the 

1  An  official  order  relative  to  these  exercises,  which  order  was  written 
in  1854,  and  is  apparently  still  in  force,  runs  thus:  "The  pupils  ought 
never  to  be  left  to  themselves  during  the  manipulations.  These  should 
always  be  preceded  by  a  conference,  in  which  are  set  forth,  with  all 
necessary  details,  the  operative  processes  relative  to  the  manipulations 
which  the  pupils  are  to  perform.  In  describing  these  operations  the 
professor  executes  them,  making  use  of  the  same  apparatus  which  the 
pupils  are  to  use.  Finally,  the  apparatus,  mounted  in  advance,  is  dis- 
played before  their  eyes,  which  indicates  all  the  dispositions  which  they 
will  have  to  observe  in  the  arrangement  of  the  pieces  which  compose  it." 
This  order  affords  a  good  example  of  the  care  and  precision  with  which 
official  instructions  are  issued  to  teachers  in  the  public  schools  in  France. 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES      367 

objects,  in  comparing  and  generalizing,  in  reasoning  without 
the  aid  of  material  examples." 

In  the  higher  primary  schools  for  boys  we  find 

"  Physics  and  Chemistry.  (Two  hours  a  week  [for  both,  not 
for  each]  during  the  three  years.)  General  Remark. —  In  each 
year  the  course  in  physics  and  chemistry  will  be  essentially  ex- 
perimental." That  is,  the  lessons  are  to  be  illustrated  by 
lecture-table  experiments. 

"  Physics.  FIRST  YEAR.  Heat.  —  In  general,  bodies  expand 
under  the  influence  of  heat.  —  Simple  experiments. — They 
expand  unequally. 

"  Temperature. —  Mercury  thermometer.  —  Graduation.  — 
Centigrade  Scale,  degree  centigrade.  —  Maximum  and  mini- 
mum thermometers,"  etc. 

The  general  course  is  the  same  for  all  three  sections,  com- 
mercial, industrial,  and  agricultural,  but  with  applications  vary- 
ing from  one  section  to  another,  "according  to  the  special 
needs  of  each." 

In  the  higher  primary  schools  for  girls  the  physics  of  the 
first  two  years  is  identical,  so  far  as  the  official  programmes 
of  topics  show,  with  that  of  the  same  years  in  the  corres- 
ponding schools  for  boys,  but  the  like  is  not  true  of  the  third 
year. 

As  the  time  allowed  for  physics  and  chemistry  together 
in  these  schools  for  girls  is  only  one  hour  a  week  for  the 
three  years,  just  one -half  as  much  as  the  time  given  to  the 
same  subjects  in  the  corresponding  school  for  boys,  it  is  evi- 
dent that  the  instruction  received  by  girls  is  comparatively 
superficial. 

In  the  first  three  years,  "  Division  Elcmentaire"  of  the  course 
in  the  lycc'es  and  colleges  for  boys,  there  are  object  lessons,  one 
hour  a  week,  which  include  a  little  physics.  A  note  of  instruc- 
tion given  in  connection  with  the  science  of  the  preparatory 


368      PHYSICS   TEACHING  IN  OTHER   COUNTRIES 

class,  and  repeated  over  and  over  again  with  reference  to  the 
science  of  subsequent  classes,  up  to  the  Classe  de  Rhetorique, 
is  the  following :  "  Professors  are  especially  charged  to  spare  no 
pains  to  make  the  demonstrations  and  the  relations  of  facts  well 
understood,  and  not  to  dictate  their  courses.  They  may,  if  they 
think  it  best,  put  into  the  hands  of  the  pupils  an  autographic 
text  or  a  book  which  will  relieve  them  from  the  necessity  of 
developing  personally  all  parts  of  the  course." 

During  the  next  three  years,  Division  de  Grammaire,  there  is 
in  the  classical  course,  and  also  in  the  " modern"  course,  a 
little  of  zoology,  of  botany,  and  of  geology,  but  there  is  nothing 
of  physics,  as  such,  or  of  chemistry,  in  either  course. 

Indeed,  there  is  in  the  classical  course  of  the  lycees  no  study 
of  physics  under  its  own  name  until  the  Classe  de  Rhetorique, 
the  ninth  year  of  the  course,  is  passed  ;  then  the  student  has,  in 
the  Classe  de  Philosophie,  five  hours  a  week  divided  between 
physics  and  chemistry,  or,  in  the  Classe  de  Mathematiques 
Elementaires ,  in  addition  to  some  study  of  elementary  mechan- 
"ics,  six  hours  a  week  divided  between  physics  and  chemistry. 
Of  course  the  physics  work  done  in  these  classes  is  elementary, 
a  fact  sufficiently  illustrated  by  the  following  list  of  "  Comple- 
ments" with  which  the  physics  programme  of  the  Classe  de 
Mathematiques  Elementaires  ends : 

"  Laws  of  falling  bodies.  —  Atwood's  machine.  —  Morin's 
machine. 

"  Proportionality  of  forces  to  accelerations.  —  Mass.  —  Its 
measure  by  means  of  weight. 

"  Pendulum.  —  Applications. 

"  Very  elementary  notions  of  work,  vis  viva,  energy,  the 
mechanical  equivalent  of  heat. 

"Various  forms  of  energy.  —  Principles  of  the  conservation 
of  energy. 

"  The  steam-engine.  —  Condenser.  —  Expansion." 

This  brings  the  student  in  the  classical  course  to  his  bacca- 
laureate. His  opportunities  to  learn  physics  have  been,  appa- 


PHYSICS   TEACHING  IN  OTHER   COUNTRIES      369 

rently,  about  the  same  as  those  afforded  by  American  colleges 
having  the  old-fashioned  non-elective  course. 

In  the  "  modern  course  "  of  the  lycces,  physics,  as  such,  is 
taken  up  earlier,  three  hours  a-  week  being  divided  between  it 
and  chemistry  in  the  Classe  de  Troisieme,  the  seventh  year. 
The  spirit -in  which  it  is  to  be  taught  is  indicated  by  the  fol- 
lowing official  extract  from  some  report  :  "  The  professor  of 
sciences  will  not  lose  sight  of  the  fact  that  the  object  of  his 
instruction  is  not  solely  to  teach  his  pupils  a  certain  number  of 
acquired  facts,  but  that  it  is  also,  particularly  in  the  course  of 
modern  studies,  where  the  sciences  hold  a  large  place,  to  con- 
tribute to  the  general  culture  of  the  mind.  He  will,  therefore, 
so  act  that  the  high  educative  virtue  peculiar  to  science,  which 
those  profit  by  who  give  themselves  up  to  it,  shall  be  in  force 
as  much  as  possible  in  his  teaching."  This  precept  is  meant 
to  apply  to  the  science  teaching  in  general ;  but  under  the  head 
of  physics  and  chemistry  the  following  direction  is  given  :  "To 
the  demonstration  of  scientific  truths  the  professor  will  add 
upon  occasion  the  exposition  of  methods  [of  measurement  or 
research]  and  the  history  of  discoveries."  The  physics  of  this 
third  class  consists  of  the  elementary  study  of  gravity  and  heat. 
In  the  next  year,  second  class,  when  four  hours  a  week  are 
divided  between  physics  and  chemistry,  the  work  deals  with 
electricity,  magnetism,  acoustics,  and  optics. 

On  leaving  the  second  class  (eighth  year)  the  student  may 
enter  the  first  class  (letters)  in  which  there  is  no  physics,  the 
first  class  (sciences),  in  which  four  hours  a  week  are  divided  be- 
tween physics  and  chemistry,  or  the  Classe  de  Mathematiques 
Elementaires,  in  which,  as  we  have  already  seen,  six  hours  a 
week  are  divided  between  physics  and  chemistry.  So  far  as  one 
can  see  by  the  official  programme,  the  physics  course  of  this  last 
class  is  precisely  the  same  for  those  who  have  come  through 
the  modern  course  as  for  those  who  have  come  through  the 
classical  course,  although  it  has  been  preceded  by  considerable 
physics  study  in  the  modern  course,  and  by  almost  none  in  the 
classical  course. 

24 


370      PHYSICS   TEACHING  IN  OTHER  COUNTRIES 

In  the  lycees  and  colleges  for  girls  there  is  no  physics,  as 
such,  until  the  third  year,  when  the  pupils  are  about  four- 
teen years  of  age.  In  this  year  two  hours  a  week  are  di- 
vided between  physics  and  chemistry,  the  former  science, 
apparently,  having  the  greater  part  of  the  time.  The  subjects 
taken  up  in  physics  are  all  under  the  headings  Gravity  and 
Heat. 

In  the  next  year,  the  fourth  of  the  course,  one  and  a  half 
hour  per  week  is  given  to  physics  and  chemistry,  the  physics 
topics  treated  being  all  under  the  headings  Acoustics  and  Optics. 
In  the  next  year,  the  last  year  of  the  regular  course,  physics  and 
chemistry  together  have  two  hours  per  week,  the  physics  relating 
to  magnetism  and  electricity. 

The  total  time,  then,  for  physics  and  chemistry  in  the  lyde 
course  for  girls  amount  to  five  and  a  half  hours  a  week  for 
one  year.  This  is  about  one-quarter  of  one  year's  work,  the 
total  number  of  hours  of  stated  instruction  being  twenty-one  per 
week  in  the  third  year  and  twenty-four  per  week  in  each  of  the 
two  following  years. 

It  appears,  then,  that  the  physics  work  of  French  schools 
is  light  and  expansive,  descriptive,  somewhat  historical,  some- 
what philosophical.  It  is,  no  doubt,  skilfully  conducted.  Yet 
we  need  not  be  surprised  that  philosophers 1  have  little  respect 
for  it,  as  a  means  of  sound  discipline,  in  comparison  with  Latin 
and  Greek ;  for  it  is  evidently  intended  to  be  an  entertaining 
and  informing  rather  than  a  formative  study. 

On  the  whole,  it  appears  that  the  best  secondary  schools  in 
America,  in  trying  the  experiment  of  teaching  physics  by  means, 
in  part,  of  laboratory  work  done  by  the  pupils,  have  little  or 
nothing  to  learn  from  the  corresponding  schools  in  France, 
Germany,  or  England.  For  France  has  apparently  never 
dreamed  of  such  an  undertaking,  Germany  has  never  seri- 


1  See  Fouillee,  Education  from  a  National  Point  of  View,  Chapter  II. 


PHYSICS    TEACHING  IN   OTHER   COUNTRIES      3/1 

ously  considered  it,  and  England  is  no  farther  along  with  it 
than  we  are  in  America,  if  indeed  she  is  as  far.  If  we  make 
a  final  and  permanent  success  of  this  venture,  as  we  seem  likely 
to  do,  Europe  will  have  an  opportunity  to  learn  from  us,  and 
we  may  in  this  way  be  able  to  repay  in  some  small  measure  the 
educational  debt  which  we  have  owed  to  her  so  long. 


Index 


[CHEMISTRY,  pp.  1-227.     PHYSICS,  pp.  229-371.] 


ACADEMIC  and  formal  treatment, 
61,  64. 

Acceleration  test  of  mass,  dis- 
cussion of  observations  on, 
283- 

Accidents  in  the  laboratory,  125. 

Action  and  reaction,  discussion  of 
observations  on,  284. 

Affinity,  147. 

Allotropism,  145. 

America,  chemical  instruction  in, 
21,  57,  60. 

Ann  Arbor,  influence  of  in  Physics, 
272. 

Apparatus  (Chemistry),  blanks 
for,  196;  care  of,  199;  dealers 
in,  199;  for  lectures,  201;  list 
of,  197. 

Apparatus  (Physics),  arrangement 
°f>  3°3  >  general,  355  ;  redupli- 
cation of,  291 ;  teacher's  record 
of,  302. 

Apparatus  cases,  351. 

Application  to  every-day  matters, 
importance  of  (Chemistry),  68, 
74,  129,  138,  177. 

Applications  (Physics),  314. 

Arithmetical  blunders  of  pupils, 
287. 

Armstrong,  Prof.  H.  E.,  on  heuris- 
tic teaching.  105,  106,  362. 

Arnott's  Elements  of  Physics,  268. 

Arrangement,  principles  of,  his- 
torico-systematic,  55,  59;  nature 
study  method,  53,  54,  56;  theo- 
retical, 53,  54,  58. 


Articulation  of  school  and  college 

work,  44-48. 
Atomic    theory,    79,  81,    154-162, 

164. 

Atomic  weight,  definition  of,  165. 
Avogadro's     hypothesis,    54,    61  ; 

incomplete  discussion  advisable, 

76. 

BALANCES,  116,  195,  255,  257, 
285. 

Battery,  theory  of,  169. 

Bending,  discussion  of  observa- 
tions on,  281. 

Bibliography  (Chemistry),  219; 
(Physics),  324  (see  also  refer- 
ences at  heads  of  chapters  and 
sections). 

Book-learning,  indirectness  of,  93. 

Britain,  chemical  instruction  in, 
!9»  57- 

Brookline  high  school,  physics  in, 

337- 
Burns,  treatment  of,  126. 

CALCULATION,  by  pupil,  on  labo- 
ratory work,  298. 
Cause,  150. 

Change  and  variety,  need  of,  251. 
Child's   experimental    knowledge, 

3T7- 

Characteristics,  of  chemical 
change,  69-75  5  °f  work  in  sci- 
ences, 8-16,  50-52. 

Charts,  202. 

Chemicals,  192. 


374 


INDEX 


Chemistry,   reasons  for  the  study 

of,  17. 

Classroom,    fittings,  etc.,  200;    in- 
struction in,   128. 
College     Entrance      Examination 

Bonrd,  47,  183,  333. 
College  entrance  (Chemistry),  38, 

39,  r7<5. 
College   entrance    (Physics),   327 ; 

history  of  the  N.  E;  A.  report  on, 

328. 
College      requirements,     stimulus 

from,  336. 

Combining  weights,  law  of,  75-79. 
Committee    of    Nine,   46,    60,  85, 

183. 
Committee    of    Ten,    29,    39,   46, 

'33- 

Committee  on  college  entrance  re- 
quirements, 39,  48,  183,  327. 

Conservation  of  matter,  173. 

Coulter,  Prof.  J.  M.,  self-elimina- 
tion in  scientific  work,  12. 

Crystals,  205. 

DEGREES,  academic,  241,  247. 

Demonstrations,  133;  experiments 
for,  134,  167,  169,  170. 

Density  of  air,  discussion  of  obser- 
vations on,  285. 

Desks,  laboratory,  189. 

Detailed  list  of  laboratory  exer- 
cises, 330-333. 

Diagrams,  202. 

Difficulties  with  which  chemistry 
contends,  22-27. 

Difficulty,  intrinsic,  of  chemistry,  24. 

Difficulty  with  words,  317. 

Double  decomposition,  168. 

Drawing,  243. 

Dynamics,  presentation  of,  341  ff. 

ELECTROLYSIS,  167. 
Electro-motive  series,  169,  202. 
Eliot,  President,  on  the  study   of 

science,  83  ;  on  the  profession  of 

teaching,  234. 


Ends  for  which  chemistry  is  taught, 
64-66,  no. 

Energy,  matter  and,  152. 

Engineering  study,  243. 

England,  teaching  in  (Chemistry), 
57,  105;  (Physics),  361. 

Equations,  how  they  are  made 
(SO2),  78-80 ;  time  for,  83  ; 
writing,  82. 

Equilibrium,  chemical,  169. 

"  Even  front  "  progression  in  labo- 
ratory work,  290. 

Every-day  matters,  application  of 
chemistry  to,  68,  74,  129,  138. 

Expansion  of  air,  preparation  of 
apparatus  for  measuring,  259. 

Experiments,  qualitative  and  quan- 
titative, 312  (see  under  quantita- 
tive). 

Explanation,  129;  equals  descrip- 
tions, 147. 

FALLACIES,  145. 

Faulty  reasoning,  88,  89. 

Form,  care  for,  251,  315. 

Formulae,  their  meaning,  78-82. 

Fouillee,  Alfred,  Education  from  a 

ATatio?ial  Point  of  View,  370. 
France,  physics  teaching  in,  365. 

GAGE'S  Elements  of  Physics,  269. 
Galvanometer    for    lecture    room, 

reflecting,  310. 
General  chemistry,  importance  of, 

208. 

Generators  for  gases,  195. 
Germany,  teaching  in  (Chemistry), 

20;   (Physics),  356. 
Glass-working,  113,  243. 
Grammar  of  science,  146. 
Grammar      schools,      quantitative 

laboratory  work  in,  320. 

HARVARD   action   on   physics   for 

admission,  270,  271. 
Harvard  Descriptive  List,  255,  259, 

271,  329. 


INDEX 


375 


Harvard  influence  on  chemical  in- 
struction, 19  ;  outline  of  require- 
ments, 69,  184. 

Heat  of  solution,  146. 

Heuristic  teaching,  19,  54,  56,  105, 
362. 

High  schools,  what  they  should  do 
in  physics,  336. 

History  of  physics,  244. 

History  of  the  teaching  of  chemis- 
try, 1 8. 

Hofmann,  experiments  of,  134,  201. 

Hoods,  laboratory,  191. 

IDENTIFICATION,  exercises  in,  178. 

Illustration,  abuse  of,  142,  143; 
absorption,  141  ;  application  of 
generalizations  to  every-day  mat- 
ters, 129,  138;  Bunsen  flame, 
89 ;  burning  hydrogen,  63 ;  dis- 
sociation of  ammonium  chloride, 
88 ;  heuristic  method,  107,  108 ; 
making  of  an  equation,  78 ;  mak- 
ing of  chlorine,  131 ;  manufac- 
ture of  aluminium,  139;  metals 
and  acids,  31,  109  ;  need  of,  129, 
140,  141 ;  origin  of  valency,  163; 
oxidation  and  reduction,  140; 
potassium  iodide  and  sulphuric 
acid,  102  ;  potassium  persul- 
phate, 81 ;  properties  of  chlo- 
rine, 95  ;  use  of  the  imagination, 
131 ;  water  of  crystallization,  96, 
144. 

Imagination  in  science,  ir,  131. 

Individual  work  and  group  work, 

293- 

"  Inductive  and  deductive,"  274. 

Intensive  rather  than  extensive 
work,  62,  101. 

Introductory  work,  49-84;  qualita- 
tive characteristics,  69;  quantita- 
tive characteristics,  73 ;  summary 
of,  68. 

KNOWLEDGE-MAKING,  9,  23,  24, 
87. 


LABORATORY  (Chemistry),  direc- 
tions for  use  in,  94;  equipment 
for,  193;  furniture  for,  189;  in- 
struction in,  85 ;  store-room  of, 
195;  structure  of,  187;  supplies 
for,  195. 

Laboratory  (Physics),  plan  and 
equipment  of,  348  ff. 

Laboratory    exercise,    length     of, 

293- 

Laboratory  manual,  use  of,  294. 
Laboratory  sections,  size  of,  292. 
Laboratory  work  alone  not  enough, 

3°4- 

Laboratory  work  (Chemistry),  di- 
rections for,  94;  general  value, 
87 ;  psychology  of,  91  ;  value  in 
chemistry,  90. 

Laboratory  work  (Physics),  prepa- 
ration for,  294 ;  record  of,  296- 
301. 

Language  and  science  study  con- 
trasted, 10,  49,  89,  92,  102,  no. 

Law,  in  natural  science,  148 ;  of 
precipitation,  146. 

"  Laws/'  inaccuracy  of  some,  279  ; 
search  for,  282. 

Lectures  and  recitations,  304  ff. 

Lecture  experiments  (Chemistry), 
134,  167,  169,170;  (Physics)  308. 

Lecture-room,  353. 

Length  of  course,  40-42. 

Liebig's  course  of  instruction  in 
chemistry,  18. 

Liquid  pressure,  313,  foot  note. 

MACGREGOR,  Prof.  J.  G.,  on  knowl- 
edge-making, 9,  23,  24,  49. 

Mach,  Prof.  Ernst,  on  the  study  of 
science,  9. 

Manipulation,  need  of  directions  in 
regard  to,  97,  112. 

Manual  labor,  relief  from,  302. 

Mass,  acceleration  test  of,  283;  in 
language  of  engineering,  347. 

Mathematics,  235,  241,  242, 

Matter  and  energy,  152. 


376 


INDEX 


Method  of  inquiry,  278. 
Method  of  verification,  277. 
Methods,  report  on,  289. 
Middle  States  Board,  action  of,  333. 
Mineralogy,  204. 
Misleading  words,  144. 

"  NATURE  STUDY,"  316. 

Nichols,  Professor,  on  research  by 

teachers,  216,  248. 
Note-book,  123-125,  298. 
Numerical   problems   (Chemistry), 

135,  136;  (Physics),  use  of,  307. 

OBSERVATION,  directions  to  assist, 
98 ;  involves  creation  of  subject 
of  study,  36,  98  ;  must  be  supple- 
mented by  text -book,  19,  136; 
what  it  implies,  87. 

Observation,  habit  of,  243,  249. 

Observations,  pool  ing  of,  281-285. 

PACKARD,  J.  C.,  physics  course  de- 
scribed by,  337. 

Perkin  and  Lean,  characteristics 
of  their  book,  56. 

Physical  chemistry,  165-171;  value 
to  the  teacher,  166,  170. 

Physical  observation,  chemistry 
founded  on,  17,  30-33,  39,  69. 

Physics,  before  or  after  chemistry, 
29-37  ;  is  chemistry  simpler  than, 

34-37- 

Physics  Teachers,  Eastern  Associ- 
ation of,  289  ff. 

Picton,  Prof.  H.,  on  heuristic  teach, 
ing,  108. 

Platform-balance,  257,  285. 

Portraits,  203. 

Preparations,  inorganic  21 1. 

Problems,  135  ;  collections  of,  136. 

Projecting  lantern,  311. 

QUALITATIVE  analysis,  171-178; 
history  of  its  use  in  introductory 
work,  18;  in  training  of  teacher, 
209,  212;  substitute  for,  178. 


Qualitative  or  quantitative  work 
for  lower  schools,  318. 

Quantitative  analysis,  its  value,  210. 

Quantitative  experiments,  benefits 
of,  120;  degree  of  exactness  of, 
114;  equipment  for,  115;  ex- 
amples of,  78,  117;  historical, 
115;  objections  to,  121 ;  time  and 
method  of  use,  119. 

Questions,  collections  of,  133; 
good  and  bad,  132. 

Quiz,  128;  abuse  of,  306. 

READING,  books  and  journals,  218- 
227,  248;  original  papers,  214. 

Reagents,  192. 

Reciprocal  proportions,  law  of,  75. 

Recognition  of  unknown  bodies, 
exercises  in,  136. 

Repetition  of  exercises,  288. 

Research,  216,  247. 

Reversible  actions,  169. 

Rowland,  Professor,  247. 

Russell,  J.  E.,  German  Higher 
Schools,  357. 

SATURATION,  145. 

Science,  objections  to  the  study  of, 
1 6 ;  reasons  for  the  study  of, 
8-16,  239;  Spencer's  reasons  for 
the  study  of,  6,  13. 

Secondary  schools,  essential  differ- 
ence in,  335. 

Self-elimination  in  scientific  work, 
12. 

Solution  tension  series,  202. 

Specialization  in  the  secondary 
school,  42-44. 

Spencer,  Herbert,  his  reasons  for 
the  study  of  science,  6,  13. 

Spring-balance,  255. 

Stability,  144. 

Steam  baths,  194. 

Strong  acids,  130,  144,  145. 

TABLES  for  laboratory  work 
(Physics),  348. 


INDEX 


377 


Teacher,  defects  in  training  of,  22 ; 
demands  on  his  time,  135;  ex- 
perimental work  for,  134,  167, 
169,  170,  216;  his  development, 
214;  his  preparation,  207-214, 
238  ;  his  private  room,  206 ;  his 
reading,  218;  need  of  his  pres- 
ence, 122,  125. 

Teachers  College,  245. 

Teachers,  number  required,  123. 

Teaching,  study  of  the  art  of,  244. 

Text-book,  choice  of,  184  ;  need  of, 
99,  101,  136;  types  of  (Physics), 
268  if. 

Torrey,  Joseph,  characteristics  of 
his  book,  58. 

Trowbridge's  New  Physics,  270. 

Tyler,  Prof.  J.  M.,  use  of  the 
imagination,  n. 


UNIFICATION,  need  of,  143. 
University  of  the    State    of    New 

York,    syllabus     of    chemistry, 

183- 

VALENCY,  162-164. 

Vassall,    Archer,    on    physics    in 

English     preparatory     schools, 

361. 

WATER  of  crystallization,  96,  144. 
Water-proofing,  253. 
Weighing,  method  of,  112,  258. 
Workshop,  352. 

Worthington's  Physical  Laboratory 
Practice,  270. 

YEAR  of  curriculum  for  chemistry, 
37-40. 


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